{ "query": { "display": "$$y^{^{\\prime\\prime}}\\left(x\\right)-3y^{^{\\prime}}\\left(x\\right)+2y=\\frac{1}{1+e^{-x}}$$", "symbolab_question": "ODE#y^{\\prime \\prime }(x)-3y^{\\prime }(x)+2y=\\frac{1}{1+e^{-x}}" }, "solution": { "level": "PERFORMED", "subject": "Calculus", "topic": "ODE", "subTopic": "ConstCoeffLinearNonHomogeneous", "default": "y=c_{1}e^{2x}+c_{2}e^{x}+(-1-e^{-x}+\\ln(1+e^{-x}))e^{2x}+\\ln(1+e^{-x})e^{x}", "meta": { "showVerify": true } }, "steps": { "type": "interim", "title": "$$y^{\\prime\\prime}\\left(x\\right)-3y^{\\prime}\\left(x\\right)+2y=\\frac{1}{1+e^{-x}}:{\\quad}y=c_{1}e^{2x}+c_{2}e^{x}+\\left(-1-e^{-x}+\\ln\\left(1+e^{-x}\\right)\\right)e^{2x}+\\ln\\left(1+e^{-x}\\right)e^{x}$$", "input": "y^{\\prime\\prime}\\left(x\\right)-3y^{\\prime}\\left(x\\right)+2y=\\frac{1}{1+e^{-x}}", "steps": [ { "type": "interim", "title": "Solve linear ODE:$${\\quad}y=c_{1}e^{2x}+c_{2}e^{x}+\\left(-1-e^{-x}+\\ln\\left(1+e^{-x}\\right)\\right)e^{2x}+\\ln\\left(1+e^{-x}\\right)e^{x}$$", "input": "y^{\\prime\\prime}\\left(x\\right)-3y^{\\prime}\\left(x\\right)+2y=\\frac{1}{1+e^{-x}}", "steps": [ { "type": "definition", "title": "Second order linear non-homogeneous differential equation with constant coefficients", "text": "A second order linear, non-homogeneous ODE has the form of $$ay''+by'+cy=g\\left(x\\right)$$" }, { "type": "step", "primary": "The general solution to $$a\\left(x\\right)y''+b\\left(x\\right)y'+c\\left(x\\right)y=g\\left(x\\right)$$ can be written as<br/>$$y=y_h+y_p$$<br/>$$y_h$$ is the solution to the homogeneous ODE $$a\\left(x\\right)y''+b\\left(x\\right)y'+c\\left(x\\right)y=0$$<br/>$$y_p$$, the particular solution, is any function that satisfies the non-homogeneous equation " }, { "type": "interim", "title": "Find $$y_h$$ by solving $$y^{\\prime\\prime}\\left(x\\right)-3y^{\\prime}\\left(x\\right)+2y=0:{\\quad}y=c_{1}e^{2x}+c_{2}e^{x}$$", "input": "y^{\\prime\\prime}\\left(x\\right)-3y^{\\prime}\\left(x\\right)+2y=0", "steps": [ { "type": "definition", "title": "Second order linear homogeneous differential equation with constant coefficients", "text": "A second order linear, homogeneous ODE has the form of $$ay''+by'+cy=0$$" }, { "type": "step", "primary": "For an equation $$ay''+by'+cy=0$$, assume a solution of the form $$e^{γx}$$", "secondary": [ "Rewrite the equation with $$y=e^{γx}$$" ], "result": "\\left(\\left(e^{γx}\\right)\\right)^{^{\\prime\\prime}}-3\\left(\\left(e^{γx}\\right)\\right)^{^{\\prime}}+2e^{γx}=0" }, { "type": "interim", "title": "Simplify $$\\left(\\left(e^{γx}\\right)\\right)^{\\prime\\prime}-3\\left(\\left(e^{γx}\\right)\\right)^{\\prime}+2e^{γx}=0:{\\quad}e^{γx}\\left(γ^{2}-3γ+2\\right)=0$$", "steps": [ { "type": "step", "result": "\\left(\\left(e^{γx}\\right)\\right)^{^{\\prime\\prime}}-3\\left(\\left(e^{γx}\\right)\\right)^{^{\\prime}}+2e^{γx}=0" }, { "type": "interim", "title": "$$\\left(e^{γx}\\right)^{\\prime\\prime}=γ^{2}e^{γx}$$", "input": "\\left(e^{γx}\\right)^{\\prime\\prime}", "steps": [ { "type": "interim", "title": "$$\\left(e^{γx}\\right)^{\\prime}=e^{γx}γ$$", "input": "\\left(e^{γx}\\right)^{\\prime}", "steps": [ { "type": "interim", "title": "Apply the chain rule:$${\\quad}e^{γx}\\left(γx\\right)^{\\prime}$$", "input": "\\left(e^{γx}\\right)^{\\prime}", "result": "=e^{γx}\\left(γx\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the chain rule: $$\\frac{df\\left(u\\right)}{dx}=\\frac{df}{du}\\cdot\\frac{du}{dx}$$", "secondary": [ "$$f=e^{u},\\:\\:u=γx$$" ], "result": "=\\left(e^{u}\\right)^{^{\\prime}}\\left(γx\\right)^{^{\\prime}}", "meta": { "practiceLink": "/practice/derivatives-practice#area=main&subtopic=Chain%20Rule", "practiceTopic": "Chain Rule" } }, { "type": "interim", "title": "$$\\left(e^{u}\\right)^{\\prime}=e^{u}$$", "input": "\\left(e^{u}\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the common derivative: $$\\left(e^{u}\\right)^{\\prime}=e^{u}$$", "result": "=e^{u}" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7cVPV4zUFISiTd+fVX6xXsrmsNRuddYPgZ8cGsLVhNNRQsU0KegSjwRVV1JfeZUqosl5PTRzFd2J0fcq0+01bpNW4Yoa9OGLIL+u1HBPyzhvQzhwSHylow7u2/8ADWpoHsIjaxJ4DvjTb2fbKjbvtlQ==" } }, { "type": "step", "result": "=e^{u}\\left(γx\\right)^{^{\\prime}}" }, { "type": "step", "primary": "Substitute back $$u=γx$$", "result": "=e^{γx}\\left(γx\\right)^{^{\\prime}}" } ], "meta": { "interimType": "Derivative Chain Rule 0Eq", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7Gvl9rbrp9vJgB3DE3RVCcBDY8sG8wkKf3KVMoxpWVQssjvX7KVUO/AeCFSId4S33iWw9g5uXzmS5KX5zIzOHZXiX35dQ/h01lIvxamZtt5M1thhQ/Ed/UbgOWE3OQBzQDrbw8lc2jRiiaaodUFzB+wS4M5VpC8qh+oehjmM1qmzPHVJGaR3CuIp5NX3rLDDQialcV/dI5TH4fXyp+ncwuA==" } }, { "type": "interim", "title": "$$\\left(γx\\right)^{\\prime}=γ$$", "input": "\\left(γx\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Take the constant out: $$\\left(a{\\cdot}f\\right)'=a{\\cdot}f'$$", "result": "=γx^{^{\\prime}}" }, { "type": "step", "primary": "Apply the common derivative: $$x^{\\prime}=1$$", "result": "=γ\\cdot\\:1" }, { "type": "step", "primary": "Simplify", "result": "=γ", "meta": { "solvingClass": "Solver" } } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7EVB+jU4LMswLFUscsVdfVSENAk/2SHMUCwaiey+GXBFDkFJVC/dxv52FMorbXyXoUpO3zWZspTvnswNQKdz3tV6EkZL7Rz6t72e1SEoLgfPvRCDs4D3rcIVpx7C72k9c" } }, { "type": "step", "result": "=e^{γx}γ" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives" } }, { "type": "step", "result": "=\\left(e^{γx}γ\\right)^{^{\\prime}}" }, { "type": "interim", "title": "$$\\left(e^{γx}γ\\right)^{\\prime}=γ^{2}e^{γx}$$", "input": "\\left(e^{γx}γ\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Take the constant out: $$\\left(a{\\cdot}f\\right)'=a{\\cdot}f'$$", "result": "=γ\\left(e^{γx}\\right)^{^{\\prime}}" }, { "type": "interim", "title": "Apply the chain rule:$${\\quad}e^{γx}\\left(γx\\right)^{\\prime}$$", "input": "\\left(e^{γx}\\right)^{\\prime}", "result": "=e^{γx}\\left(γx\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the chain rule: $$\\frac{df\\left(u\\right)}{dx}=\\frac{df}{du}\\cdot\\frac{du}{dx}$$", "secondary": [ "$$f=e^{u},\\:\\:u=γx$$" ], "result": "=\\left(e^{u}\\right)^{^{\\prime}}\\left(γx\\right)^{^{\\prime}}", "meta": { "practiceLink": "/practice/derivatives-practice#area=main&subtopic=Chain%20Rule", "practiceTopic": "Chain Rule" } }, { "type": "interim", "title": "$$\\left(e^{u}\\right)^{\\prime}=e^{u}$$", "input": "\\left(e^{u}\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the common derivative: $$\\left(e^{u}\\right)^{\\prime}=e^{u}$$", "result": "=e^{u}" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7cVPV4zUFISiTd+fVX6xXsrmsNRuddYPgZ8cGsLVhNNRQsU0KegSjwRVV1JfeZUqosl5PTRzFd2J0fcq0+01bpNW4Yoa9OGLIL+u1HBPyzhvQzhwSHylow7u2/8ADWpoHsIjaxJ4DvjTb2fbKjbvtlQ==" } }, { "type": "step", "result": "=e^{u}\\left(γx\\right)^{^{\\prime}}" }, { "type": "step", "primary": "Substitute back $$u=γx$$", "result": "=e^{γx}\\left(γx\\right)^{^{\\prime}}" } ], "meta": { "interimType": "Derivative Chain Rule 0Eq", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7Gvl9rbrp9vJgB3DE3RVCcBDY8sG8wkKf3KVMoxpWVQssjvX7KVUO/AeCFSId4S33iWw9g5uXzmS5KX5zIzOHZXiX35dQ/h01lIvxamZtt5M1thhQ/Ed/UbgOWE3OQBzQDrbw8lc2jRiiaaodUFzB+wS4M5VpC8qh+oehjmM1qmzPHVJGaR3CuIp5NX3rLDDQialcV/dI5TH4fXyp+ncwuA==" } }, { "type": "interim", "title": "$$\\left(γx\\right)^{\\prime}=γ$$", "input": "\\left(γx\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Take the constant out: $$\\left(a{\\cdot}f\\right)'=a{\\cdot}f'$$", "result": "=γx^{^{\\prime}}" }, { "type": "step", "primary": "Apply the common derivative: $$x^{\\prime}=1$$", "result": "=γ\\cdot\\:1" }, { "type": "step", "primary": "Simplify", "result": "=γ", "meta": { "solvingClass": "Solver" } } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7EVB+jU4LMswLFUscsVdfVSENAk/2SHMUCwaiey+GXBFDkFJVC/dxv52FMorbXyXoUpO3zWZspTvnswNQKdz3tV6EkZL7Rz6t72e1SEoLgfPvRCDs4D3rcIVpx7C72k9c" } }, { "type": "step", "result": "=γe^{γx}γ" }, { "type": "interim", "title": "Simplify $$γe^{γx}γ:{\\quad}γ^{2}e^{γx}$$", "input": "γe^{γx}γ", "result": "=γ^{2}e^{γx}", "steps": [ { "type": "step", "primary": "Apply exponent rule: $$a^b\\cdot\\:a^c=a^{b+c}$$", "secondary": [ "$$γγ=\\:γ^{1+1}$$" ], "result": "=e^{γx}γ^{1+1}", "meta": { "practiceLink": "/practice/exponent-practice", "practiceTopic": "Expand FOIL" } }, { "type": "step", "primary": "Add the numbers: $$1+1=2$$", "result": "=e^{γx}γ^{2}" } ], "meta": { "solvingClass": "Solver", "interimType": "Generic Simplify Specific 1Eq", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7Ogc+QG1cya0zQe2NAtljy96GQqufR6tr2vPxOUv7H++vcvW4o70lTWJV7TqReTsbmx4rCXhbsN+br+uOYP22UU3kCh3oevUunZ7/b0qFKBStCRMtul5SOs/SBwPTbaWuzHQDH6pWoNP3G07HzBhaLA==" } } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives" } }, { "type": "step", "result": "=γ^{2}e^{γx}" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives" } }, { "type": "step", "result": "γ^{2}e^{γx}-3\\left(e^{γx}\\right)^{^{\\prime}}+2e^{γx}=0" }, { "type": "interim", "title": "$$\\left(e^{γx}\\right)^{\\prime}=e^{γx}γ$$", "input": "\\left(e^{γx}\\right)^{\\prime}", "steps": [ { "type": "interim", "title": "Apply the chain rule:$${\\quad}e^{γx}\\left(γx\\right)^{\\prime}$$", "input": "\\left(e^{γx}\\right)^{\\prime}", "result": "=e^{γx}\\left(γx\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the chain rule: $$\\frac{df\\left(u\\right)}{dx}=\\frac{df}{du}\\cdot\\frac{du}{dx}$$", "secondary": [ "$$f=e^{u},\\:\\:u=γx$$" ], "result": "=\\left(e^{u}\\right)^{^{\\prime}}\\left(γx\\right)^{^{\\prime}}", "meta": { "practiceLink": "/practice/derivatives-practice#area=main&subtopic=Chain%20Rule", "practiceTopic": "Chain Rule" } }, { "type": "interim", "title": "$$\\left(e^{u}\\right)^{\\prime}=e^{u}$$", "input": "\\left(e^{u}\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the common derivative: $$\\left(e^{u}\\right)^{\\prime}=e^{u}$$", "result": "=e^{u}" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7cVPV4zUFISiTd+fVX6xXsrmsNRuddYPgZ8cGsLVhNNRQsU0KegSjwRVV1JfeZUqosl5PTRzFd2J0fcq0+01bpNW4Yoa9OGLIL+u1HBPyzhvQzhwSHylow7u2/8ADWpoHsIjaxJ4DvjTb2fbKjbvtlQ==" } }, { "type": "step", "result": "=e^{u}\\left(γx\\right)^{^{\\prime}}" }, { "type": "step", "primary": "Substitute back $$u=γx$$", "result": "=e^{γx}\\left(γx\\right)^{^{\\prime}}" } ], "meta": { "interimType": "Derivative Chain Rule 0Eq", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7Gvl9rbrp9vJgB3DE3RVCcBDY8sG8wkKf3KVMoxpWVQssjvX7KVUO/AeCFSId4S33iWw9g5uXzmS5KX5zIzOHZXiX35dQ/h01lIvxamZtt5M1thhQ/Ed/UbgOWE3OQBzQDrbw8lc2jRiiaaodUFzB+wS4M5VpC8qh+oehjmM1qmzPHVJGaR3CuIp5NX3rLDDQialcV/dI5TH4fXyp+ncwuA==" } }, { "type": "interim", "title": "$$\\left(γx\\right)^{\\prime}=γ$$", "input": "\\left(γx\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Take the constant out: $$\\left(a{\\cdot}f\\right)'=a{\\cdot}f'$$", "result": "=γx^{^{\\prime}}" }, { "type": "step", "primary": "Apply the common derivative: $$x^{\\prime}=1$$", "result": "=γ\\cdot\\:1" }, { "type": "step", "primary": "Simplify", "result": "=γ", "meta": { "solvingClass": "Solver" } } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7EVB+jU4LMswLFUscsVdfVSENAk/2SHMUCwaiey+GXBFDkFJVC/dxv52FMorbXyXoUpO3zWZspTvnswNQKdz3tV6EkZL7Rz6t72e1SEoLgfPvRCDs4D3rcIVpx7C72k9c" } }, { "type": "step", "result": "=e^{γx}γ" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives" } }, { "type": "step", "result": "γ^{2}e^{γx}-3e^{γx}γ+2e^{γx}=0" }, { "type": "step", "primary": "Factor $$e^{γx}$$", "result": "e^{γx}\\left(γ^{2}-3γ+2\\right)=0" } ], "meta": { "interimType": "Generic Simplify Specific 1Eq" } }, { "type": "step", "result": "e^{γx}\\left(γ^{2}-3γ+2\\right)=0" }, { "type": "interim", "title": "Solve $$e^{γx}\\left(γ^{2}-3γ+2\\right)=0:{\\quad}γ=2,\\:γ=1$$", "input": "e^{γx}\\left(γ^{2}-3γ+2\\right)=0", "steps": [ { "type": "step", "primary": "Since $$e^{γx}\\ne\\:0$$, solving $$e^{γx}\\left(γ^{2}-3γ+2\\right)=0$$<br/> is equivalent to solving the quadratic equation $$γ^{2}-3γ+2=0$$", "result": "γ^{2}-3γ+2=0" }, { "type": "interim", "title": "Solve with the quadratic formula", "input": "γ^{2}-3γ+2=0", "result": "{γ}_{1,\\:2}=\\frac{-\\left(-3\\right)\\pm\\:\\sqrt{\\left(-3\\right)^{2}-4\\cdot\\:1\\cdot\\:2}}{2\\cdot\\:1}", "steps": [ { "type": "definition", "title": "Quadratic Equation Formula:", "text": "For a quadratic equation of the form $$ax^2+bx+c=0$$ the solutions are <br/>$${\\quad}x_{1,\\:2}=\\frac{-b\\pm\\sqrt{b^2-4ac}}{2a}$$" }, { "type": "step", "primary": "For $${\\quad}a=1,\\:b=-3,\\:c=2$$", "result": "{γ}_{1,\\:2}=\\frac{-\\left(-3\\right)\\pm\\:\\sqrt{\\left(-3\\right)^{2}-4\\cdot\\:1\\cdot\\:2}}{2\\cdot\\:1}" } ], "meta": { "interimType": "Solving The Quadratic Equation With Quadratic Formula Definition 0Eq", "gptData": "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" } }, { "type": "interim", "title": "$$\\sqrt{\\left(-3\\right)^{2}-4\\cdot\\:1\\cdot\\:2}=1$$", "input": "\\sqrt{\\left(-3\\right)^{2}-4\\cdot\\:1\\cdot\\:2}", "result": "{γ}_{1,\\:2}=\\frac{-\\left(-3\\right)\\pm\\:1}{2\\cdot\\:1}", "steps": [ { "type": "step", "primary": "Apply exponent rule: $$\\left(-a\\right)^{n}=a^{n},\\:$$if $$n$$ is even", "secondary": [ "$$\\left(-3\\right)^{2}=3^{2}$$" ], "result": "=\\sqrt{3^{2}-4\\cdot\\:1\\cdot\\:2}" }, { "type": "step", "primary": "Multiply the numbers: $$4\\cdot\\:1\\cdot\\:2=8$$", "result": "=\\sqrt{3^{2}-8}" }, { "type": "step", "primary": "$$3^{2}=9$$", "result": "=\\sqrt{9-8}" }, { "type": "step", "primary": "Subtract the numbers: $$9-8=1$$", "result": "=\\sqrt{1}" }, { "type": "step", "primary": "Apply rule $$\\sqrt{1}=1$$", "result": "=1" } ], "meta": { "solvingClass": "Solver", "interimType": "Solver", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s77dtxLd9UeyppCvogsL4v83GW/jTwUrqHAcqr1cHDsBBw4ba/3KCEGXsM04IlGc/HzMFYmi1F5Hg/ibpEToVnY247KVn/9CN730bZvRQSpulUlJGhz/9/49m9VyFXtj5ecZb+NPBSuocByqvVwcOwEEDVEq/Lyx8C1I/8Q6ctddo=" } }, { "type": "step", "primary": "Separate the solutions", "result": "{γ}_{1}=\\frac{-\\left(-3\\right)+1}{2\\cdot\\:1},\\:{γ}_{2}=\\frac{-\\left(-3\\right)-1}{2\\cdot\\:1}" }, { "type": "interim", "title": "$$γ=\\frac{-\\left(-3\\right)+1}{2\\cdot\\:1}:{\\quad}2$$", "input": "\\frac{-\\left(-3\\right)+1}{2\\cdot\\:1}", "steps": [ { "type": "step", "primary": "Apply rule $$-\\left(-a\\right)=a$$", "result": "=\\frac{3+1}{2\\cdot\\:1}" }, { "type": "step", "primary": "Add the numbers: $$3+1=4$$", "result": "=\\frac{4}{2\\cdot\\:1}" }, { "type": "step", "primary": "Multiply the numbers: $$2\\cdot\\:1=2$$", "result": "=\\frac{4}{2}" }, { "type": "step", "primary": "Divide the numbers: $$\\frac{4}{2}=2$$", "result": "=2" } ], "meta": { "solvingClass": "Solver", "interimType": "Solver", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7BRRger6gkjQuZFNUJO1CQrJqVPiSqeELumwKNYa9UokgJ/ZZA32ZInFBpDtxBfiKRcASOqRpLIeIyUBzgC+nUDMZsebS69oihnBNBSMiS5tayBhLPCAZUhx1M1IbRaw+d7DaIenKLTiwZv2anSwwjQ==" } }, { "type": "interim", "title": "$$γ=\\frac{-\\left(-3\\right)-1}{2\\cdot\\:1}:{\\quad}1$$", "input": "\\frac{-\\left(-3\\right)-1}{2\\cdot\\:1}", "steps": [ { "type": "step", "primary": "Apply rule $$-\\left(-a\\right)=a$$", "result": "=\\frac{3-1}{2\\cdot\\:1}" }, { "type": "step", "primary": "Subtract the numbers: $$3-1=2$$", "result": "=\\frac{2}{2\\cdot\\:1}" }, { "type": "step", "primary": "Multiply the numbers: $$2\\cdot\\:1=2$$", "result": "=\\frac{2}{2}" }, { "type": "step", "primary": "Apply rule $$\\frac{a}{a}=1$$", "result": "=1" } ], "meta": { "solvingClass": "Solver", "interimType": "Solver", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7fb8/QwpiZ9fKB0o6NPD4MrJqVPiSqeELumwKNYa9UokgJ/ZZA32ZInFBpDtxBfiK7J5E5gGi2xwchkRMjoVJ7jMZsebS69oihnBNBSMiS5sFZg/Lik3tDW+uYEraYwryd7DaIenKLTiwZv2anSwwjQ==" } }, { "type": "step", "primary": "The solutions to the quadratic equation are:", "result": "γ=2,\\:γ=1" } ], "meta": { "interimType": "Generic Solve Title 1Eq" } }, { "type": "step", "result": "γ=2,\\:γ=1" }, { "type": "step", "primary": "For two real roots $$γ_{1}\\ne\\:γ_{2}$$, the general solution takes the form:$${\\quad}y=c_{1}e^{γ_{1}\\:x}+c_{2}e^{γ_{2}\\:x}$$", "result": "y=c_{1}e^{2x}+c_{2}e^{x}" } ], "meta": { "solvingClass": "ODE", "interimType": "Generic Find By Solving Title 2Eq" } }, { "type": "interim", "title": "Find $$y_{p}$$ that satisfies $$y^{\\prime\\prime}\\left(x\\right)-3y^{\\prime}\\left(x\\right)+2y=\\frac{1}{1+e^{-x}}:{\\quad}y_{p}=\\left(-1-e^{-x}+\\ln\\left(1+e^{-x}\\right)\\right)e^{2x}+\\ln\\left(1+e^{-x}\\right)e^{x}$$", "steps": [ { "type": "step", "primary": "For the non-homogeneous part $$g\\left(x\\right)=\\frac{1}{1+e^{-x}}$$, assume a solution of the form:<br/>$$y_{p}=u_{1}y_{1}+u_{2}y_{2}$$<br/>Where $$y_{1}$$ and $$y_{2}$$ are solutions of homogeneous equation $$y_{h}=c_{1}y_{1}+c_{2}y_{2}$$, <br/> $${u_{1}}$$ and $${u_{2}}$$ are solutions to the system of equations:<br/>$$\\begin{pmatrix}\\left(u_{1}\\right)^{^{\\prime}}y_{1}+\\left(u_{2}\\right)^{^{\\prime}}y_{2}=0\\\\\\left(u_{1}\\right)^{^{\\prime}}\\left(y_{1}\\right)^{^{\\prime}}+\\left(u_{2}\\right)^{^{\\prime}}\\left(y_{2}\\right)^{^{\\prime}}=g\\left(x\\right)\\end{pmatrix}$$<br/>Which implies", "secondary": [ "$$u_{1}=\\int\\:-\\frac{y_{2}g\\left(x\\right)}{W\\left(y_{1},\\:y_{2}\\right)}dx$$", "$$u_{2}=\\int\\:\\frac{y_{1}g\\left(x\\right)}{W\\left(y_{1},\\:y_{2}\\right)}dx$$", "Where Wronskian $$W\\left(y_{1},\\:y_{2}\\right)=y_{1}\\left(y_{2}\\right)^{^{\\prime}}-\\left(y_{1}\\right)^{^{\\prime}}y_{2}$$" ] }, { "type": "step", "primary": "Homogeneous solutions:", "secondary": [ "$$y_{1}=e^{2x}$$", "$$y_{2}=e^{x}$$" ] }, { "type": "interim", "title": "$$\\left(y_{1}\\right)^{^{\\prime}}:{\\quad}e^{2x}\\cdot\\:2$$", "input": "\\left(e^{2x}\\right)^{\\prime}", "steps": [ { "type": "interim", "title": "Apply the chain rule:$${\\quad}e^{2x}\\left(2x\\right)^{\\prime}$$", "input": "\\left(e^{2x}\\right)^{\\prime}", "result": "=e^{2x}\\left(2x\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the chain rule: $$\\frac{df\\left(u\\right)}{dx}=\\frac{df}{du}\\cdot\\frac{du}{dx}$$", "secondary": [ "$$f=e^{u},\\:\\:u=2x$$" ], "result": "=\\left(e^{u}\\right)^{^{\\prime}}\\left(2x\\right)^{^{\\prime}}", "meta": { "practiceLink": "/practice/derivatives-practice#area=main&subtopic=Chain%20Rule", "practiceTopic": "Chain Rule" } }, { "type": "interim", "title": "$$\\left(e^{u}\\right)^{\\prime}=e^{u}$$", "input": "\\left(e^{u}\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the common derivative: $$\\left(e^{u}\\right)^{\\prime}=e^{u}$$", "result": "=e^{u}" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7cVPV4zUFISiTd+fVX6xXsrmsNRuddYPgZ8cGsLVhNNRQsU0KegSjwRVV1JfeZUqosl5PTRzFd2J0fcq0+01bpNW4Yoa9OGLIL+u1HBPyzhvQzhwSHylow7u2/8ADWpoHsIjaxJ4DvjTb2fbKjbvtlQ==" } }, { "type": "step", "result": "=e^{u}\\left(2x\\right)^{^{\\prime}}" }, { "type": "step", "primary": "Substitute back $$u=2x$$", "result": "=e^{2x}\\left(2x\\right)^{^{\\prime}}" } ], "meta": { "interimType": "Derivative Chain Rule 0Eq", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s71GjX8/WOlVQoR3720Yfm9aRMrCnJ6xySUWC3ZSXynKYHjZ0JmeAC3ZSEmMxWRNYu6XlRsqVFSAmW95ptSxLnUn04noP5Jb9NWXDshKwxOQOcTTG1MQjF4JOCdGL5fDxZfH6kVvau+ENR7awhAU+mEsZ11qduazhyKAKmPCwtn/zCT5AuTjawvypQebt2ubgAJLd1ohke2Wgml78++2zI0g==" } }, { "type": "interim", "title": "$$\\left(2x\\right)^{\\prime}=2$$", "input": "\\left(2x\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Take the constant out: $$\\left(a{\\cdot}f\\right)'=a{\\cdot}f'$$", "result": "=2x^{^{\\prime}}" }, { "type": "step", "primary": "Apply the common derivative: $$x^{\\prime}=1$$", "result": "=2\\cdot\\:1" }, { "type": "step", "primary": "Simplify", "result": "=2", "meta": { "solvingClass": "Solver" } } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7iEluvAhAB6qVseHmXOoGm8PQlVFV646ejpUuEWqujX2QuIxj9K+Upo9l4tAcwN/gSLdINoPD2MyLmUXT+YnlMolkIAcH8DCZe9Bzo2oZbtQQDuUeqnBwgbzjs2dJUq2K" } }, { "type": "step", "result": "=e^{2x}\\cdot\\:2" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives" } }, { "type": "interim", "title": "$$\\left(y_{2}\\right)^{^{\\prime}}:{\\quad}e^{x}$$", "input": "\\left(e^{x}\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the common derivative: $$\\left(e^{x}\\right)^{\\prime}=e^{x}$$", "result": "=e^{x}" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7CBKEUujzBr/OwXKSSv8Lr7msNRuddYPgZ8cGsLVhNNRQsU0KegSjwRVV1JfeZUqoYkL0LptyesbbdTForD1TM+mtSooHHgz8yj8VjvtwX+TK+f0kTaFpliuy3OWH0/pl" } }, { "type": "step", "primary": "$$W\\left(y_{1},\\:y_{2}\\right)=y_{1}\\left(y_{2}\\right)^{^{\\prime}}-\\left(y_{1}\\right)^{^{\\prime}}y_{2}$$", "result": "W\\left(y_{1},\\:y_{2}\\right)=e^{2x}e^{x}-e^{2x}\\cdot\\:2e^{x}" }, { "type": "step", "result": "W\\left(y_{1},\\:y_{2}\\right)=-e^{3x}" }, { "type": "step", "primary": "$$u_{1}=\\int\\:-\\frac{y_{2}g\\left(x\\right)}{W\\left(y_{1},\\:y_{2}\\right)}dx$$", "result": "u_{1}=\\int\\:-\\frac{e^{x}\\frac{1}{1+e^{-x}}}{-e^{3x}}dx" }, { "type": "interim", "title": "$$\\int\\:-\\frac{e^{x}\\frac{1}{1+e^{-x}}}{-e^{3x}}dx=-1-e^{-x}+\\ln\\left(1+e^{-x}\\right)+C$$", "input": "\\int\\:-\\frac{e^{x}\\frac{1}{1+e^{-x}}}{-e^{3x}}dx", "steps": [ { "type": "interim", "title": "Simplify $$-\\frac{e^{x}\\frac{1}{1+e^{-x}}}{-e^{3x}}:{\\quad}\\frac{1}{e^{2x}\\left(1+e^{-x}\\right)}$$", "input": "-\\frac{e^{x}\\frac{1}{1+e^{-x}}}{-e^{3x}}", "steps": [ { "type": "step", "primary": "Apply the fraction rule: $$\\frac{a}{-b}=-\\frac{a}{b}$$", "result": "=-\\left(-\\frac{e^{x}\\frac{1}{e^{-x}+1}}{e^{3x}}\\right)" }, { "type": "step", "primary": "Apply rule $$-\\left(-a\\right)=a$$", "result": "=\\frac{e^{x}\\frac{1}{1+e^{-x}}}{e^{3x}}" }, { "type": "interim", "title": "Multiply $$e^{x}\\frac{1}{1+e^{-x}}\\::{\\quad}\\frac{e^{x}}{1+e^{-x}}$$", "input": "e^{x}\\frac{1}{1+e^{-x}}", "result": "=\\frac{\\frac{e^{x}}{1+e^{-x}}}{e^{3x}}", "steps": [ { "type": "step", "primary": "Multiply fractions: $$a\\cdot\\frac{b}{c}=\\frac{a\\:\\cdot\\:b}{c}$$", "result": "=\\frac{1\\cdot\\:e^{x}}{1+e^{-x}}" }, { "type": "step", "primary": "Multiply: $$1\\cdot\\:e^{x}=e^{x}$$", "result": "=\\frac{e^{x}}{1+e^{-x}}" } ], "meta": { "interimType": "Generic Multiply Title 1Eq" } }, { "type": "step", "primary": "Apply the fraction rule: $$\\frac{\\frac{b}{c}}{a}=\\frac{b}{c\\:\\cdot\\:a}$$", "result": "=\\frac{e^{x}}{\\left(1+e^{-x}\\right)e^{3x}}" }, { "type": "step", "primary": "Apply exponent rule: $$\\frac{x^{a}}{x^{b}}\\:=\\:x^{a-b}$$", "secondary": [ "$$\\frac{e^{x}}{e^{3x}}=e^{x-3x}=e^{-2x}$$" ], "result": "=\\frac{1}{e^{2x}\\left(e^{-x}+1\\right)}", "meta": { "practiceLink": "/practice/exponent-practice", "practiceTopic": "Expand FOIL" } } ], "meta": { "solvingClass": "Solver", "interimType": "Algebraic Manipulation Simplify Title 1Eq" } }, { "type": "step", "result": "=\\int\\:\\frac{1}{e^{2x}\\left(1+e^{-x}\\right)}dx" }, { "type": "step", "primary": "Apply exponent rule: $$\\frac{1}{a^b}=a^{-b}$$", "secondary": [ "$$\\frac{1}{e^{2x}\\left(1+e^{-x}\\right)}=e^{-2x}\\frac{1}{\\left(1+e^{-x}\\right)}$$" ], "result": "=\\int\\:e^{-2x}\\frac{1}{1+e^{-x}}dx", "meta": { "practiceLink": "/practice/exponent-practice", "practiceTopic": "Expand FOIL" } }, { "type": "interim", "title": "Simplify $$e^{-2x}\\frac{1}{1+e^{-x}}:{\\quad}\\frac{e^{-2x}}{1+e^{-x}}$$", "input": "e^{-2x}\\frac{1}{1+e^{-x}}", "steps": [ { "type": "step", "primary": "Multiply fractions: $$a\\cdot\\frac{b}{c}=\\frac{a\\:\\cdot\\:b}{c}$$", "result": "=\\frac{1\\cdot\\:e^{-2x}}{1+e^{-x}}" }, { "type": "step", "primary": "Multiply: $$1\\cdot\\:e^{-2x}=e^{-2x}$$", "result": "=\\frac{e^{-2x}}{1+e^{-x}}" } ], "meta": { "solvingClass": "Solver", "interimType": "Algebraic Manipulation Simplify Title 1Eq" } }, { "type": "step", "result": "=\\int\\:\\frac{e^{-2x}}{1+e^{-x}}dx" }, { "type": "interim", "title": "Apply u-substitution", "input": "\\int\\:\\frac{e^{-2x}}{1+e^{-x}}dx", "steps": [ { "type": "definition", "title": "Integral Substitution definition", "text": "$$\\int\\:f\\left(g\\left(x\\right)\\right)\\cdot\\:g'\\left(x\\right)dx=\\int\\:f\\left(u\\right)du,\\:\\quad\\:u=g\\left(x\\right)$$", "secondary": [ "Substitute: $$u=1+e^{-x}$$" ] }, { "type": "interim", "title": "$$\\frac{du}{dx}=-e^{-x}$$", "input": "\\left(1+e^{-x}\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the Sum/Difference Rule: $$\\left(f{\\pm}g\\right)'=f'{\\pm}g'$$", "result": "=1^{^{\\prime}}+\\left(e^{-x}\\right)^{^{\\prime}}" }, { "type": "interim", "title": "$$1^{\\prime}=0$$", "input": "1^{\\prime}", "steps": [ { "type": "step", "primary": "Derivative of a constant: $$\\frac{d}{dx}\\left({a}\\right)=0$$", "result": "=0" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7/5pHl7jX6nP6oSkaDnJ8dqboRT4ICWDw+vXUOyCoK0ujkVi15I8rBefLi4Iyt2wr8D4yaPBYvrqNvcxJbQLVhNUy0PGUeVurnmhVFT+4jBc=" } }, { "type": "interim", "title": "$$\\left(e^{-x}\\right)^{\\prime}=-e^{-x}$$", "input": "\\left(e^{-x}\\right)^{\\prime}", "steps": [ { "type": "interim", "title": "Apply the chain rule:$${\\quad}e^{-x}\\left(-x\\right)^{\\prime}$$", "input": "\\left(e^{-x}\\right)^{\\prime}", "result": "=e^{-x}\\left(-x\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the chain rule: $$\\frac{df\\left(u\\right)}{dx}=\\frac{df}{du}\\cdot\\frac{du}{dx}$$", "secondary": [ "$$f=e^{u},\\:\\:u=-x$$" ], "result": "=\\left(e^{u}\\right)^{^{\\prime}}\\left(-x\\right)^{^{\\prime}}", "meta": { "practiceLink": "/practice/derivatives-practice#area=main&subtopic=Chain%20Rule", "practiceTopic": "Chain Rule" } }, { "type": "interim", "title": "$$\\left(e^{u}\\right)^{\\prime}=e^{u}$$", "input": "\\left(e^{u}\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the common derivative: $$\\left(e^{u}\\right)^{\\prime}=e^{u}$$", "result": "=e^{u}" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7cVPV4zUFISiTd+fVX6xXsrmsNRuddYPgZ8cGsLVhNNRQsU0KegSjwRVV1JfeZUqosl5PTRzFd2J0fcq0+01bpNW4Yoa9OGLIL+u1HBPyzhvQzhwSHylow7u2/8ADWpoHsIjaxJ4DvjTb2fbKjbvtlQ==" } }, { "type": "step", "result": "=e^{u}\\left(-x\\right)^{^{\\prime}}" }, { "type": "step", "primary": "Substitute back $$u=-x$$", "result": "=e^{-x}\\left(-x\\right)^{^{\\prime}}" } ], "meta": { "interimType": "Derivative Chain Rule 0Eq", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7GSIQlKG9310R1ElGl3CVfaRMrCnJ6xySUWC3ZSXynKYHjZ0JmeAC3ZSEmMxWRNYu6XlRsqVFSAmW95ptSxLnUn04noP5Jb9NWXDshKwxOQOB6LdUC4vDg25Wev+HuCzhfH6kVvau+ENR7awhAU+mEsZ11qduazhyKAKmPCwtn/zCT5AuTjawvypQebt2ubgAJLd1ohke2Wgml78++2zI0g==" } }, { "type": "interim", "title": "$$\\left(-x\\right)^{\\prime}=-1$$", "input": "\\left(-x\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Take the constant out: $$\\left(a{\\cdot}f\\right)'=a{\\cdot}f'$$", "result": "=-x^{^{\\prime}}" }, { "type": "step", "primary": "Apply the common derivative: $$x^{\\prime}=1$$", "result": "=-1" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7UM4LDHFZjLzDjY8O/P1Ab8PQlVFV646ejpUuEWqujX2QuIxj9K+Upo9l4tAcwN/g69GyryCsZzNNAEljQyUl0eplVd2gGs/MYc2HGVEvpw+gc+cK9cns8BOox/q2OecQ" } }, { "type": "step", "result": "=e^{-x}\\left(-1\\right)" }, { "type": "step", "primary": "Simplify", "result": "=-e^{-x}", "meta": { "solvingClass": "Solver" } } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives" } }, { "type": "step", "result": "=0-e^{-x}" }, { "type": "step", "primary": "Simplify", "result": "=-e^{-x}", "meta": { "solvingClass": "Solver" } } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives" } }, { "type": "step", "primary": "$$\\quad\\Rightarrow\\:du=-e^{-x}dx$$" }, { "type": "step", "primary": "$$\\quad\\Rightarrow\\:dx=\\left(-e^{x}\\right)du$$" }, { "type": "step", "result": "=\\int\\:\\frac{e^{-2x}}{u}\\left(-e^{x}\\right)du" }, { "type": "interim", "title": "Simplify $$\\frac{e^{-2x}}{u}\\left(-e^{x}\\right):{\\quad}-\\frac{e^{-x}}{u}$$", "input": "\\frac{e^{-2x}}{u}\\left(-e^{x}\\right)", "steps": [ { "type": "step", "primary": "Remove parentheses: $$\\left(-a\\right)=-a$$", "result": "=-\\frac{e^{-2x}}{u}e^{x}" }, { "type": "step", "primary": "Multiply fractions: $$a\\cdot\\frac{b}{c}=\\frac{a\\:\\cdot\\:b}{c}$$", "result": "=-\\frac{e^{-2x}e^{x}}{u}" }, { "type": "interim", "title": "$$e^{-2x}e^{x}=e^{-x}$$", "input": "e^{-2x}e^{x}", "steps": [ { "type": "step", "primary": "Apply exponent rule: $$a^b\\cdot\\:a^c=a^{b+c}$$", "secondary": [ "$$e^{-2x}e^{x}=\\:e^{-2x+x}$$" ], "result": "=e^{-2x+x}", "meta": { "practiceLink": "/practice/exponent-practice", "practiceTopic": "Expand FOIL" } }, { "type": "step", "primary": "Add similar elements: $$-2x+x=-x$$", "result": "=e^{-x}" } ], "meta": { "solvingClass": "Solver", "interimType": "Solver", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7FowRfh810+9bpnHz+cS5glXTSum/z5kLpMzXS1UJIex9upyvpSJ+axyVrxsRkkAK/z//r+dXk7h9vxeDCLuZqpKYea5wkxBOE0qTl4Xr3ldhJ8W6EF+Iw3rbaWc1uD4S" } }, { "type": "step", "result": "=-\\frac{e^{-x}}{u}" } ], "meta": { "solvingClass": "Solver", "interimType": "Algebraic Manipulation Simplify Title 1Eq" } }, { "type": "step", "result": "=\\int\\:-\\frac{e^{-x}}{u}du" }, { "type": "interim", "title": "$$u=1+e^{-x}\\quad\\Rightarrow\\quad\\:e^{-x}=u-1$$", "input": "1+e^{-x}=u", "steps": [ { "type": "interim", "title": "Move $$1\\:$$to the right side", "input": "1+e^{-x}=u", "result": "e^{-x}=u-1", "steps": [ { "type": "step", "primary": "Subtract $$1$$ from both sides", "result": "1+e^{-x}-1=u-1" }, { "type": "step", "primary": "Simplify", "result": "e^{-x}=u-1" } ], "meta": { "interimType": "Move to the Right Title 1Eq", "gptData": "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" } } ], "meta": { "solvingClass": "Equations", "interimType": "Equations" } }, { "type": "step", "result": "=\\int\\:-\\frac{u-1}{u}du" } ], "meta": { "interimType": "Integral U Substitution 1Eq", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7l7+Hp9GxvB/5I+4/5L7s70hb/s63F1m65pyLf6NpX6R8JURM0P4tpPzEvj8+iLpfLI71+ylVDvwHghUiHeEt93Gam9ro5jdhRGQuTP5rGCB4l9+XUP4dNZSL8WpmbbeT4j27KJ23AvytEJKx61QAnz9psU5ldmEOJUKwbBRrOQKqkIX6kseCKdEth+cILnwy7iOSVUKCvHweh2lT4eXSw8TaqbJFwAzvwA3RhTAPNgI=" } }, { "type": "step", "result": "=\\int\\:-\\frac{u-1}{u}du" }, { "type": "step", "primary": "Take the constant out: $$\\int{a\\cdot{f\\left(x\\right)}dx}=a\\cdot\\int{f\\left(x\\right)dx}$$", "result": "=-\\int\\:\\frac{u-1}{u}du" }, { "type": "interim", "title": "Expand $$\\frac{u-1}{u}:{\\quad}1-\\frac{1}{u}$$", "input": "\\frac{u-1}{u}", "steps": [ { "type": "step", "primary": "Apply the fraction rule: $$\\frac{a\\pm\\:b}{c}=\\frac{a}{c}\\pm\\:\\frac{b}{c}$$", "secondary": [ "$$\\frac{u-1}{u}=\\frac{u}{u}-\\frac{1}{u}$$" ], "result": "=\\frac{u}{u}-\\frac{1}{u}" }, { "type": "step", "primary": "Apply rule $$\\frac{a}{a}=1$$", "secondary": [ "$$\\frac{u}{u}=1$$" ], "result": "=1-\\frac{1}{u}" } ], "meta": { "solvingClass": "Solver", "interimType": "Algebraic Manipulation Expand Title 1Eq", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7tmJ+4RiVlGO9IgEmgGy2pQCWKUbvV6WK3fDUgFtg3Q9Q7GQHzM2DoFG/VzJXJyOZQXlgPFRFcFhBuY7t6rjpnIEFMST8lDZxn1Yq5HMKVTvDpCb0LomfCc/BDlzuuIuGIbxXdJTNg73LMCcLa8vk0Q==" } }, { "type": "step", "result": "=-\\int\\:1-\\frac{1}{u}du" }, { "type": "step", "primary": "Apply the Sum Rule: $$\\int{f\\left(x\\right){\\pm}g\\left(x\\right)}dx=\\int{f\\left(x\\right)}dx{\\pm}\\int{g\\left(x\\right)}dx$$", "result": "=-\\left(\\int\\:1du-\\int\\:\\frac{1}{u}du\\right)" }, { "type": "interim", "title": "$$\\int\\:1du=u$$", "input": "\\int\\:1du", "steps": [ { "type": "step", "primary": "Integral of a constant: $$\\int{a}dx=ax$$", "result": "=1\\cdot\\:u" }, { "type": "step", "primary": "Simplify", "result": "=u", "meta": { "solvingClass": "Solver" } } ], "meta": { "solvingClass": "Integrals", "interimType": "Integrals" } }, { "type": "interim", "title": "$$\\int\\:\\frac{1}{u}du=\\ln\\left(u\\right)$$", "input": "\\int\\:\\frac{1}{u}du", "steps": [ { "type": "step", "primary": "Use the common integral:$$\\quad\\:\\int\\:\\frac{1}{u}du=\\ln\\left(u\\right),\\:$$assuming a complex-valued logarithm", "result": "=\\ln\\left(u\\right)" } ], "meta": { "solvingClass": "Integrals", "interimType": "Integrals" } }, { "type": "step", "result": "=-\\left(u-\\ln\\left(u\\right)\\right)" }, { "type": "step", "primary": "Substitute back $$u=1+e^{-x}$$", "result": "=-\\left(1+e^{-x}-\\ln\\left(1+e^{-x}\\right)\\right)" }, { "type": "step", "primary": "Simplify", "result": "=-1-e^{-x}+\\ln\\left(1+e^{-x}\\right)", "meta": { "solvingClass": "Solver" } }, { "type": "step", "primary": "Add a constant to the solution", "result": "=-1-e^{-x}+\\ln\\left(1+e^{-x}\\right)+C", "meta": { "title": { "extension": "If $$\\frac{dF\\left(x\\right)}{dx}=f\\left(x\\right)$$ then $$\\int{f\\left(x\\right)}dx=F\\left(x\\right)+C$$" } } } ], "meta": { "solvingClass": "Integrals", "interimType": "Integrals" } }, { "type": "step", "result": "u_{1}=-1-e^{-x}+\\ln\\left(1+e^{-x}\\right)" }, { "type": "step", "primary": "$$u_{2}=\\int\\:\\frac{y_{1}g\\left(x\\right)}{W\\left(y_{1},\\:y_{2}\\right)}dx$$", "result": "u_{2}=\\int\\:\\frac{e^{2x}\\frac{1}{1+e^{-x}}}{-e^{3x}}dx" }, { "type": "interim", "title": "$$\\int\\:\\frac{e^{2x}\\frac{1}{1+e^{-x}}}{-e^{3x}}dx=\\ln\\left(1+e^{-x}\\right)+C$$", "input": "\\int\\:\\frac{e^{2x}\\frac{1}{1+e^{-x}}}{-e^{3x}}dx", "steps": [ { "type": "step", "primary": "Take the constant out: $$\\int{a\\cdot{f\\left(x\\right)}dx}=a\\cdot\\int{f\\left(x\\right)dx}$$", "result": "=-\\int\\:\\frac{e^{2x}\\frac{1}{1+e^{-x}}}{e^{3x}}dx" }, { "type": "step", "primary": "Apply exponent rule: $$\\frac{1}{a^b}=a^{-b}$$", "secondary": [ "$$\\frac{e^{2x}\\frac{1}{1+e^{-x}}}{e^{3x}}=\\left(e^{2x}\\frac{1}{1+e^{-x}}\\right)e^{-3x}$$" ], "result": "=-\\int\\:e^{2x}\\frac{1}{1+e^{-x}}e^{-3x}dx", "meta": { "practiceLink": "/practice/exponent-practice", "practiceTopic": "Expand FOIL" } }, { "type": "interim", "title": "Simplify $$e^{2x}\\frac{1}{1+e^{-x}}e^{-3x}:{\\quad}\\frac{e^{-x}}{1+e^{-x}}$$", "input": "e^{2x}\\frac{1}{1+e^{-x}}e^{-3x}", "steps": [ { "type": "step", "primary": "Apply exponent rule: $$a^b\\cdot\\:a^c=a^{b+c}$$", "secondary": [ "$$e^{2x}e^{-3x}=\\:e^{2x-3x}$$" ], "result": "=\\frac{1}{1+e^{-x}}e^{2x-3x}", "meta": { "practiceLink": "/practice/exponent-practice", "practiceTopic": "Expand FOIL" } }, { "type": "step", "primary": "Add similar elements: $$2x-3x=-x$$", "result": "=\\frac{1}{1+e^{-x}}e^{-x}" }, { "type": "step", "primary": "Multiply fractions: $$a\\cdot\\frac{b}{c}=\\frac{a\\:\\cdot\\:b}{c}$$", "result": "=\\frac{1\\cdot\\:e^{-x}}{1+e^{-x}}" }, { "type": "step", "primary": "Multiply: $$1\\cdot\\:e^{-x}=e^{-x}$$", "result": "=\\frac{e^{-x}}{1+e^{-x}}" } ], "meta": { "solvingClass": "Solver", "interimType": "Algebraic Manipulation Simplify Title 1Eq" } }, { "type": "step", "result": "=-\\int\\:\\frac{e^{-x}}{1+e^{-x}}dx" }, { "type": "interim", "title": "Apply u-substitution", "input": "\\int\\:\\frac{e^{-x}}{1+e^{-x}}dx", "steps": [ { "type": "definition", "title": "Integral Substitution definition", "text": "$$\\int\\:f\\left(g\\left(x\\right)\\right)\\cdot\\:g'\\left(x\\right)dx=\\int\\:f\\left(u\\right)du,\\:\\quad\\:u=g\\left(x\\right)$$", "secondary": [ "Substitute: $$u=1+e^{-x}$$" ] }, { "type": "interim", "title": "$$\\frac{du}{dx}=-e^{-x}$$", "input": "\\left(1+e^{-x}\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the Sum/Difference Rule: $$\\left(f{\\pm}g\\right)'=f'{\\pm}g'$$", "result": "=1^{^{\\prime}}+\\left(e^{-x}\\right)^{^{\\prime}}" }, { "type": "interim", "title": "$$1^{\\prime}=0$$", "input": "1^{\\prime}", "steps": [ { "type": "step", "primary": "Derivative of a constant: $$\\frac{d}{dx}\\left({a}\\right)=0$$", "result": "=0" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7/5pHl7jX6nP6oSkaDnJ8dqboRT4ICWDw+vXUOyCoK0ujkVi15I8rBefLi4Iyt2wr8D4yaPBYvrqNvcxJbQLVhNUy0PGUeVurnmhVFT+4jBc=" } }, { "type": "interim", "title": "$$\\left(e^{-x}\\right)^{\\prime}=-e^{-x}$$", "input": "\\left(e^{-x}\\right)^{\\prime}", "steps": [ { "type": "interim", "title": "Apply the chain rule:$${\\quad}e^{-x}\\left(-x\\right)^{\\prime}$$", "input": "\\left(e^{-x}\\right)^{\\prime}", "result": "=e^{-x}\\left(-x\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the chain rule: $$\\frac{df\\left(u\\right)}{dx}=\\frac{df}{du}\\cdot\\frac{du}{dx}$$", "secondary": [ "$$f=e^{u},\\:\\:u=-x$$" ], "result": "=\\left(e^{u}\\right)^{^{\\prime}}\\left(-x\\right)^{^{\\prime}}", "meta": { "practiceLink": "/practice/derivatives-practice#area=main&subtopic=Chain%20Rule", "practiceTopic": "Chain Rule" } }, { "type": "interim", "title": "$$\\left(e^{u}\\right)^{\\prime}=e^{u}$$", "input": "\\left(e^{u}\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Apply the common derivative: $$\\left(e^{u}\\right)^{\\prime}=e^{u}$$", "result": "=e^{u}" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7cVPV4zUFISiTd+fVX6xXsrmsNRuddYPgZ8cGsLVhNNRQsU0KegSjwRVV1JfeZUqosl5PTRzFd2J0fcq0+01bpNW4Yoa9OGLIL+u1HBPyzhvQzhwSHylow7u2/8ADWpoHsIjaxJ4DvjTb2fbKjbvtlQ==" } }, { "type": "step", "result": "=e^{u}\\left(-x\\right)^{^{\\prime}}" }, { "type": "step", "primary": "Substitute back $$u=-x$$", "result": "=e^{-x}\\left(-x\\right)^{^{\\prime}}" } ], "meta": { "interimType": "Derivative Chain Rule 0Eq", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7GSIQlKG9310R1ElGl3CVfaRMrCnJ6xySUWC3ZSXynKYHjZ0JmeAC3ZSEmMxWRNYu6XlRsqVFSAmW95ptSxLnUn04noP5Jb9NWXDshKwxOQOB6LdUC4vDg25Wev+HuCzhfH6kVvau+ENR7awhAU+mEsZ11qduazhyKAKmPCwtn/zCT5AuTjawvypQebt2ubgAJLd1ohke2Wgml78++2zI0g==" } }, { "type": "interim", "title": "$$\\left(-x\\right)^{\\prime}=-1$$", "input": "\\left(-x\\right)^{\\prime}", "steps": [ { "type": "step", "primary": "Take the constant out: $$\\left(a{\\cdot}f\\right)'=a{\\cdot}f'$$", "result": "=-x^{^{\\prime}}" }, { "type": "step", "primary": "Apply the common derivative: $$x^{\\prime}=1$$", "result": "=-1" } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7UM4LDHFZjLzDjY8O/P1Ab8PQlVFV646ejpUuEWqujX2QuIxj9K+Upo9l4tAcwN/g69GyryCsZzNNAEljQyUl0eplVd2gGs/MYc2HGVEvpw+gc+cK9cns8BOox/q2OecQ" } }, { "type": "step", "result": "=e^{-x}\\left(-1\\right)" }, { "type": "step", "primary": "Simplify", "result": "=-e^{-x}", "meta": { "solvingClass": "Solver" } } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives" } }, { "type": "step", "result": "=0-e^{-x}" }, { "type": "step", "primary": "Simplify", "result": "=-e^{-x}", "meta": { "solvingClass": "Solver" } } ], "meta": { "solvingClass": "Derivatives", "interimType": "Derivatives" } }, { "type": "step", "primary": "$$\\quad\\Rightarrow\\:du=-e^{-x}dx$$" }, { "type": "step", "primary": "$$\\quad\\Rightarrow\\:dx=\\left(-e^{x}\\right)du$$" }, { "type": "step", "result": "=\\int\\:\\frac{e^{-x}}{u}\\left(-e^{x}\\right)du" }, { "type": "interim", "title": "Simplify $$\\frac{e^{-x}}{u}\\left(-e^{x}\\right):{\\quad}-\\frac{1}{u}$$", "input": "\\frac{e^{-x}}{u}\\left(-e^{x}\\right)", "steps": [ { "type": "step", "primary": "Remove parentheses: $$\\left(-a\\right)=-a$$", "result": "=-\\frac{e^{-x}}{u}e^{x}" }, { "type": "step", "primary": "Multiply fractions: $$a\\cdot\\frac{b}{c}=\\frac{a\\:\\cdot\\:b}{c}$$", "result": "=-\\frac{e^{-x}e^{x}}{u}" }, { "type": "interim", "title": "$$e^{-x}e^{x}=1$$", "input": "e^{-x}e^{x}", "steps": [ { "type": "step", "primary": "Apply exponent rule: $$a^b\\cdot\\:a^c=a^{b+c}$$", "secondary": [ "$$e^{-x}e^{x}=\\:e^{-x+x}$$" ], "result": "=e^{-x+x}", "meta": { "practiceLink": "/practice/exponent-practice", "practiceTopic": "Expand FOIL" } }, { "type": "step", "primary": "Add similar elements: $$-x+x=0$$", "result": "=e^{0}" }, { "type": "step", "primary": "Apply rule $$a^{0}=1,\\:a\\ne\\:0$$", "result": "=1" } ], "meta": { "solvingClass": "Solver", "interimType": "Solver", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7xTyy5ngoavpgJhDWv/GYNd6GQqufR6tr2vPxOUv7H++P6Ubiv/bIrpol3G9QIK7hIyLGydo+KydlY3bqCHx2y94B8gB1xs8WTDicQ2y4oR0=" } }, { "type": "step", "result": "=-\\frac{1}{u}" } ], "meta": { "solvingClass": "Solver", "interimType": "Algebraic Manipulation Simplify Title 1Eq" } }, { "type": "step", "result": "=\\int\\:-\\frac{1}{u}du" } ], "meta": { "interimType": "Integral U Substitution 1Eq", "gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7l7+Hp9GxvB/5I+4/5L7s7/WOhQiXKi9yVklE5DMKcxeg4hnUrXtr12VFUZl/drzdB42dCZngAt2UhJjMVkTWLsN5vRWJvr0V/8T6RtR0CSAgHP4YqWkh5OOHaSrQ/l8RM0i8HyTLkatLR0zdJkCzvf8DOFkEB41JAUo0zfus0lAEuDOVaQvKofqHoY5jNapscN6G3wC0aNOpX3GMtOsWhImpXFf3SOUx+H18qfp3MLg=" } }, { "type": "step", "result": "=-\\int\\:-\\frac{1}{u}du" }, { "type": "step", "primary": "Take the constant out: $$\\int{a\\cdot{f\\left(x\\right)}dx}=a\\cdot\\int{f\\left(x\\right)dx}$$", "result": "=-\\left(-\\int\\:\\frac{1}{u}du\\right)" }, { "type": "step", "primary": "Use the common integral:$$\\quad\\:\\int\\:\\frac{1}{u}du=\\ln\\left(u\\right),\\:$$assuming a complex-valued logarithm", "result": "=-\\left(-\\ln\\left(u\\right)\\right)" }, { "type": "step", "primary": "Substitute back $$u=1+e^{-x}$$", "result": "=-\\left(-\\ln\\left(1+e^{-x}\\right)\\right)" }, { "type": "step", "primary": "Simplify", "result": "=\\ln\\left(1+e^{-x}\\right)", "meta": { "solvingClass": "Solver" } }, { "type": "step", "primary": "Add a constant to the solution", "result": "=\\ln\\left(1+e^{-x}\\right)+C", "meta": { "title": { "extension": "If $$\\frac{dF\\left(x\\right)}{dx}=f\\left(x\\right)$$ then $$\\int{f\\left(x\\right)}dx=F\\left(x\\right)+C$$" } } } ], "meta": { "solvingClass": "Integrals", "interimType": "Integrals" } }, { "type": "step", "result": "u_{2}=\\ln\\left(1+e^{-x}\\right)" }, { "type": "step", "primary": "$$y_{p}=u_{1}y_{1}+u_{2}y_{2}$$", "result": "y_{p}=\\left(-1-e^{-x}+\\ln\\left(1+e^{-x}\\right)\\right)e^{2x}+\\ln\\left(1+e^{-x}\\right)e^{x}" }, { "type": "step", "primary": "A particular solution $$y_{p}$$ to$${\\quad}y^{\\prime\\prime}\\left(x\\right)-3y^{\\prime}\\left(x\\right)+2y=\\frac{1}{1+e^{-x}}{\\quad}$$is:", "result": "y_{p}=\\left(-1-e^{-x}+\\ln\\left(1+e^{-x}\\right)\\right)e^{2x}+\\ln\\left(1+e^{-x}\\right)e^{x}" } ], "meta": { "interimType": "Generic Find That Satisfies Title 2Eq" } }, { "type": "step", "primary": "The general solution $$y=y_h+y_p$$ is:", "result": "y=c_{1}e^{2x}+c_{2}e^{x}+\\left(-1-e^{-x}+\\ln\\left(1+e^{-x}\\right)\\right)e^{2x}+\\ln\\left(1+e^{-x}\\right)e^{x}" } ], "meta": { "interimType": "ODE Solve Linear 0Eq" } }, { "type": "step", "result": "y=c_{1}e^{2x}+c_{2}e^{x}+\\left(-1-e^{-x}+\\ln\\left(1+e^{-x}\\right)\\right)e^{2x}+\\ln\\left(1+e^{-x}\\right)e^{x}" } ], "meta": { "solvingClass": "ODE" } }, "meta": { "showVerify": true } }