{
"query": {
"display": "$$\\sum_{n=0}^{\\infty\\:}\\frac{5}{2+3^{n}}$$",
"symbolab_question": "BIG_OPERATOR#\\sum _{n=0}^{\\infty }\\frac{5}{2+3^{n}}"
},
"solution": {
"level": "PERFORMED",
"subject": "Calculus",
"topic": "Series",
"subTopic": "Convergence",
"default": "\\mathrm{converges}"
},
"steps": {
"type": "interim",
"title": "Check convergence of $$\\sum_{n=0}^{\\infty\\:}\\frac{5}{2+3^{n}}:{\\quad}$$converges",
"input": "\\sum_{n=0}^{\\infty\\:}\\frac{5}{2+3^{n}}",
"steps": [
{
"type": "step",
"primary": "Apply the constant multiplication rule: $$\\sum{c\\cdot{a_{n}}}=c\\cdot\\sum{a_{n}}$$",
"result": "=5\\cdot\\:\\sum_{n=0}^{\\infty\\:}\\frac{1}{2+3^{n}}"
},
{
"type": "interim",
"title": "Apply Series Ratio Test:$${\\quad}$$converges",
"input": "\\sum_{n=0}^{\\infty\\:}\\frac{1}{2+3^{n}}",
"steps": [
{
"type": "definition",
"title": "Series Ratio Test:",
"text": "If there exists an $$N$$ so that for all $$n\\ge{N},\\:{\\quad}a_n\\neq{0}$$ and $$\\lim_{n\\to\\infty}|\\frac{a_{n+1}}{a_{n}}|=L:$$<br/>$${\\quad}$$If $$L<1$$, then $$\\sum{a_n}$$ converges<br/>$${\\quad}$$If $$L>1$$, then $$\\sum{a_n}$$ diverges<br/>$${\\quad}$$If $$L=1$$, then the test is inconclusive"
},
{
"type": "step",
"primary": "$$\\left|\\frac{a_{n+1}}{a_n}\\right|=\\left|\\frac{\\frac{1}{2+3^{\\left(n+1\\right)}}}{\\frac{1}{2+3^{n}}}\\right|$$"
},
{
"type": "interim",
"title": "Simplify $$\\left|\\frac{\\frac{1}{2+3^{\\left(n+1\\right)}}}{\\frac{1}{2+3^{n}}}\\right|:{\\quad}\\frac{\\left|2+3^{n}\\right|}{\\left|2+3^{n+1}\\right|}$$",
"steps": [
{
"type": "step",
"result": "=\\left|\\frac{\\frac{1}{2+3^{n+1}}}{\\frac{1}{2+3^{n}}}\\right|"
},
{
"type": "interim",
"title": "Simplify $$\\frac{\\frac{1}{2+3^{n+1}}}{\\frac{1}{2+3^{n}}}:{\\quad}\\frac{2+3^{n}}{2+3^{n+1}}$$",
"input": "\\frac{\\frac{1}{2+3^{n+1}}}{\\frac{1}{2+3^{n}}}",
"result": "=\\left|\\frac{2+3^{n}}{2+3^{n+1}}\\right|",
"steps": [
{
"type": "step",
"primary": "Divide fractions: $$\\frac{\\frac{a}{b}}{\\frac{c}{d}}=\\frac{a\\cdot\\:d}{b\\cdot\\:c}$$",
"result": "=\\frac{1\\cdot\\:\\left(2+3^{n}\\right)}{\\left(2+3^{n+1}\\right)\\cdot\\:1}"
},
{
"type": "step",
"primary": "Refine",
"result": "=\\frac{2+3^{n}}{2+3^{n+1}}"
}
],
"meta": {
"interimType": "Algebraic Manipulation Simplify Title 1Eq"
}
},
{
"type": "step",
"primary": "Apply absolute rule: $$\\left|\\frac{a}{b}\\right|\\:=\\frac{\\left|a\\right|}{\\left|b\\right|}$$",
"result": "=\\frac{\\left|2+3^{n}\\right|}{\\left|2+3^{n+1}\\right|}"
}
],
"meta": {
"solvingClass": "Solver",
"interimType": "Algebraic Manipulation Simplify Title 1Eq"
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{\\left|2+3^{n}\\right|}{\\left|2+3^{n+1}\\right|}\\right)=\\frac{1}{3}$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{\\left|2+3^{n}\\right|}{\\left|2+3^{n+1}\\right|}\\right)",
"steps": [
{
"type": "step",
"primary": "$$2+3^{n}$$ is positive when $$n\\to\\:\\infty\\:$$. Therefore $$\\left|2+3^{n}\\right|=2+3^{n}$$",
"result": "=\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2+3^{n}}{\\left|2+3^{n+1}\\right|}\\right)"
},
{
"type": "step",
"primary": "$$2+3^{n+1}$$ is positive when $$n\\to\\:\\infty\\:$$. Therefore $$\\left|2+3^{n+1}\\right|=2+3^{n+1}$$",
"result": "=\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2+3^{n}}{2+3^{n+1}}\\right)"
},
{
"type": "interim",
"title": "Divide by $$3^{n+1}:\\:\\frac{\\frac{2}{3^{n+1}}+\\frac{1}{3}}{\\frac{2}{3^{n+1}}+1}$$",
"input": "\\frac{2+3^{n}}{2+3^{n+1}}",
"result": "=\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{\\frac{2}{3^{n+1}}+\\frac{1}{3}}{\\frac{2}{3^{n+1}}+1}\\right)",
"steps": [
{
"type": "step",
"primary": "Divide by $$3^{n+1}$$",
"result": "=\\frac{\\frac{2}{3^{n+1}}+\\frac{3^{n}}{3^{n+1}}}{\\frac{2}{3^{n+1}}+\\frac{3^{n+1}}{3^{n+1}}}"
},
{
"type": "step",
"primary": "Refine",
"result": "=\\frac{\\frac{2}{3^{n+1}}+\\frac{1}{3}}{\\frac{2}{3^{n+1}}+1}"
}
],
"meta": {
"interimType": "Generic Divide By 2Eq"
}
},
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}[\\frac{f\\left(x\\right)}{g\\left(x\\right)}]=\\frac{\\lim_{x\\to{a}}{f\\left(x\\right)}}{\\lim_{x\\to{a}}{g\\left(x\\right)}},\\:\\quad\\lim_{x\\to{a}}{g\\left(x\\right)}\\neq0$$<br/>With the exception of indeterminate form",
"result": "=\\frac{\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2}{3^{n+1}}+\\frac{1}{3}\\right)}{\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2}{3^{n+1}}+1\\right)}",
"meta": {
"title": {
"extension": "Indeterminate Forms:<br/>$$\\frac{\\pm\\infty}{\\pm\\infty}$$<br/>$$\\frac{0}{0}$$<br/>$$\\pm\\infty\\cdot0$$<br/>$$0^0$$<br/>$$1^{\\pm\\infty}$$<br/>$$\\infty^{0}$$<br/>$$\\infty-\\infty$$"
}
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2}{3^{n+1}}+\\frac{1}{3}\\right)=\\frac{1}{3}$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2}{3^{n+1}}+\\frac{1}{3}\\right)",
"steps": [
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}[f\\left(x\\right)\\pm{g\\left(x\\right)}]=\\lim_{x\\to{a}}{f\\left(x\\right)}\\pm\\lim_{x\\to{a}}{g\\left(x\\right)}$$<br/>With the exception of indeterminate form",
"result": "=\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2}{3^{n+1}}\\right)+\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{1}{3}\\right)",
"meta": {
"title": {
"extension": "Indeterminate Forms:<br/>$$\\frac{\\pm\\infty}{\\pm\\infty}$$<br/>$$\\frac{0}{0}$$<br/>$$\\pm\\infty\\cdot0$$<br/>$$0^0$$<br/>$$1^{\\pm\\infty}$$<br/>$$\\infty^{0}$$<br/>$$\\infty-\\infty$$"
}
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2}{3^{n+1}}\\right)=0$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2}{3^{n+1}}\\right)",
"steps": [
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}[c\\cdot{f\\left(x\\right)}]=c\\cdot\\lim_{x\\to{a}}{f\\left(x\\right)}$$",
"result": "=2\\cdot\\:\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{1}{3^{n+1}}\\right)"
},
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}[\\frac{f\\left(x\\right)}{g\\left(x\\right)}]=\\frac{\\lim_{x\\to{a}}{f\\left(x\\right)}}{\\lim_{x\\to{a}}{g\\left(x\\right)}},\\:\\quad\\lim_{x\\to{a}}{g\\left(x\\right)}\\neq0$$<br/>With the exception of indeterminate form",
"result": "=2\\cdot\\:\\frac{\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)}{\\lim_{n\\to\\:\\infty\\:}\\left(3^{n+1}\\right)}",
"meta": {
"title": {
"extension": "Indeterminate Forms:<br/>$$\\frac{\\pm\\infty}{\\pm\\infty}$$<br/>$$\\frac{0}{0}$$<br/>$$\\pm\\infty\\cdot0$$<br/>$$0^0$$<br/>$$1^{\\pm\\infty}$$<br/>$$\\infty^{0}$$<br/>$$\\infty-\\infty$$"
}
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)=1$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)",
"steps": [
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}{c}=c$$",
"result": "=1"
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(3^{n+1}\\right)=\\infty\\:$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(3^{n+1}\\right)",
"steps": [
{
"type": "interim",
"title": "Apply exponent rules",
"input": "3^{n+1}",
"result": "=\\lim_{n\\to\\:\\infty\\:}\\left(e^{\\left(n+1\\right)\\ln\\left(3\\right)}\\right)",
"steps": [
{
"type": "step",
"primary": "Apply exponent rule: $$a^{x}=e^{\\ln\\left(a^{x}\\right)}$$",
"result": "=e^{\\ln\\left(3^{n+1}\\right)}",
"meta": {
"practiceLink": "/practice/exponent-practice",
"practiceTopic": "Expand FOIL"
}
},
{
"type": "step",
"primary": "Apply log rule: $$\\ln\\left(a^{x}\\right)=x\\cdot\\ln\\left(a\\right)$$",
"result": "=e^{\\left(n+1\\right)\\ln\\left(3\\right)}",
"meta": {
"practiceLink": "/practice/logarithms-practice",
"practiceTopic": "Expand FOIL"
}
}
],
"meta": {
"interimType": "Apply Exp Rules 0Eq"
}
},
{
"type": "interim",
"title": "Apply the Limit Chain Rule:$${\\quad}\\infty\\:$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(e^{\\left(n+1\\right)\\ln\\left(3\\right)}\\right)",
"steps": [
{
"type": "definition",
"title": "Limit Chain Rule",
"text": "if $$\\lim_{u\\:\\to\\:b}\\:f\\left(u\\right)=L,\\:$$and $$\\lim_{x\\:\\to\\:a}g\\left(x\\right)=b,\\:$$and $$f\\left(x\\right)\\:$$is continuous at $$x=b$$<br/>$$\\quad$$Then: $$\\lim_{x\\:\\to\\:a}\\:f\\left(g\\left(x\\right)\\right)=L$$",
"secondary": [
"$$g\\left(n\\right)=\\left(n+1\\right)\\ln\\left(3\\right),\\:f\\left(u\\right)=e^{u}$$"
]
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(\\left(n+1\\right)\\ln\\left(3\\right)\\right)=\\infty\\:$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(\\left(n+1\\right)\\ln\\left(3\\right)\\right)",
"steps": [
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}[c\\cdot{f\\left(x\\right)}]=c\\cdot\\lim_{x\\to{a}}{f\\left(x\\right)}$$",
"result": "=\\ln\\left(3\\right)\\cdot\\:\\lim_{n\\to\\:\\infty\\:}\\left(n+1\\right)"
},
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}[f\\left(x\\right)\\pm{g\\left(x\\right)}]=\\lim_{x\\to{a}}{f\\left(x\\right)}\\pm\\lim_{x\\to{a}}{g\\left(x\\right)}$$<br/>With the exception of indeterminate form",
"result": "=\\ln\\left(3\\right)\\left(\\lim_{n\\to\\:\\infty\\:}\\left(n\\right)+\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)\\right)",
"meta": {
"title": {
"extension": "Indeterminate Forms:<br/>$$\\frac{\\pm\\infty}{\\pm\\infty}$$<br/>$$\\frac{0}{0}$$<br/>$$\\pm\\infty\\cdot0$$<br/>$$0^0$$<br/>$$1^{\\pm\\infty}$$<br/>$$\\infty^{0}$$<br/>$$\\infty-\\infty$$"
}
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(n\\right)=\\infty\\:$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(n\\right)",
"steps": [
{
"type": "step",
"primary": "Apply the common limit: $$\\lim_{n\\to\\:\\infty\\:}\\left(n\\right)=\\infty\\:$$",
"result": "=\\infty\\:"
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)=1$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)",
"steps": [
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}{c}=c$$",
"result": "=1"
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "step",
"result": "=\\ln\\left(3\\right)\\left(\\infty\\:+1\\right)"
},
{
"type": "interim",
"title": "Simplify $$\\ln\\left(3\\right)\\left(\\infty\\:+1\\right):{\\quad}\\infty\\:$$",
"input": "\\ln\\left(3\\right)\\left(\\infty\\:+1\\right)",
"result": "=\\infty\\:",
"steps": [
{
"type": "interim",
"title": "$$\\infty\\:+1=\\infty\\:$$",
"input": "\\infty\\:+1",
"steps": [
{
"type": "step",
"primary": "Apply Infinity Property: $$\\infty\\:+c=\\infty\\:$$",
"result": "=\\infty\\:"
}
],
"meta": {
"interimType": "N/A"
}
},
{
"type": "step",
"result": "=\\ln\\left(3\\right)\\left(\\infty\\:\\right)"
},
{
"type": "interim",
"title": "$$\\ln\\left(3\\right)\\left(\\infty\\:\\right)=\\infty\\:$$",
"input": "\\ln\\left(3\\right)\\left(\\infty\\:\\right)",
"steps": [
{
"type": "step",
"primary": "Apply Infinity Property: $$c\\cdot\\infty=\\infty$$",
"result": "=\\infty\\:"
}
],
"meta": {
"interimType": "N/A"
}
},
{
"type": "step",
"result": "=\\infty\\:"
}
],
"meta": {
"solvingClass": "Solver",
"interimType": "Generic Simplify Specific 1Eq",
"gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7Yh4w7EfCxZSg4ozeO+skXBgUlp2a3w1QZHYsaqXCjTxwkKGJWEPFPk38sdJMsyPIwhWwQYyckKycWgIwD4f3sPC30sSftAIFS6Qkpy19IkqxSGm+I7f73Ci1MIDs4v5cqT2ATb/SVwJa8gQiZNBNYLCI2sSeA74029n2yo277ZU="
}
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "interim",
"title": "$$\\lim_{u\\to\\:\\infty\\:}\\left(e^{u}\\right)=\\infty\\:$$",
"input": "\\lim_{u\\to\\:\\infty\\:}\\left(e^{u}\\right)",
"steps": [
{
"type": "step",
"primary": "Apply the common limit: $$\\lim_{u\\to\\:\\infty\\:}\\left(e^{u}\\right)=\\infty\\:$$",
"result": "=\\infty\\:"
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "step",
"primary": "By the chain rule:",
"result": "=\\infty\\:"
}
],
"meta": {
"interimType": "Limit Chain Rule 0Eq",
"practiceLink": "/practice/limits-practice#area=main&subtopic=Chain%20Rule",
"practiceTopic": "Limit Chain Rule"
}
},
{
"type": "step",
"result": "=\\infty\\:"
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "step",
"result": "=2\\cdot\\:\\frac{1}{\\infty\\:}"
},
{
"type": "interim",
"title": "Simplify $$2\\cdot\\:\\frac{1}{\\infty\\:}:{\\quad}0$$",
"input": "2\\cdot\\:\\frac{1}{\\infty\\:}",
"result": "=0",
"steps": [
{
"type": "step",
"primary": "Apply Infinity Property: $$\\frac{c}{\\infty}=0$$",
"result": "=2\\cdot\\:0"
},
{
"type": "step",
"primary": "Apply rule $$0\\cdot\\:a=0$$",
"result": "=0"
}
],
"meta": {
"solvingClass": "Solver",
"interimType": "Generic Simplify Specific 1Eq",
"gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7/OsC643lXZbU+VEjF1qvioOn9HZuLHQfol+FkTFV5erehkKrn0era9rz8TlL+x/vZuJKdCFsPJy1+5gBMEc9doEFMST8lDZxn1Yq5HMKVTuF2Uk9xnPPKEGoObx02AbXJCTae4I8X+gaGFYzQzhr2qjWqX1f6iAOqMbShkzd9w0="
}
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{1}{3}\\right)=\\frac{1}{3}$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{1}{3}\\right)",
"steps": [
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}{c}=c$$",
"result": "=\\frac{1}{3}"
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "step",
"result": "=0+\\frac{1}{3}"
},
{
"type": "step",
"primary": "Simplify",
"result": "=\\frac{1}{3}",
"meta": {
"solvingClass": "Solver"
}
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2}{3^{n+1}}+1\\right)=1$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2}{3^{n+1}}+1\\right)",
"steps": [
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}[f\\left(x\\right)\\pm{g\\left(x\\right)}]=\\lim_{x\\to{a}}{f\\left(x\\right)}\\pm\\lim_{x\\to{a}}{g\\left(x\\right)}$$<br/>With the exception of indeterminate form",
"result": "=\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2}{3^{n+1}}\\right)+\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)",
"meta": {
"title": {
"extension": "Indeterminate Forms:<br/>$$\\frac{\\pm\\infty}{\\pm\\infty}$$<br/>$$\\frac{0}{0}$$<br/>$$\\pm\\infty\\cdot0$$<br/>$$0^0$$<br/>$$1^{\\pm\\infty}$$<br/>$$\\infty^{0}$$<br/>$$\\infty-\\infty$$"
}
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2}{3^{n+1}}\\right)=0$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{2}{3^{n+1}}\\right)",
"steps": [
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}[c\\cdot{f\\left(x\\right)}]=c\\cdot\\lim_{x\\to{a}}{f\\left(x\\right)}$$",
"result": "=2\\cdot\\:\\lim_{n\\to\\:\\infty\\:}\\left(\\frac{1}{3^{n+1}}\\right)"
},
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}[\\frac{f\\left(x\\right)}{g\\left(x\\right)}]=\\frac{\\lim_{x\\to{a}}{f\\left(x\\right)}}{\\lim_{x\\to{a}}{g\\left(x\\right)}},\\:\\quad\\lim_{x\\to{a}}{g\\left(x\\right)}\\neq0$$<br/>With the exception of indeterminate form",
"result": "=2\\cdot\\:\\frac{\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)}{\\lim_{n\\to\\:\\infty\\:}\\left(3^{n+1}\\right)}",
"meta": {
"title": {
"extension": "Indeterminate Forms:<br/>$$\\frac{\\pm\\infty}{\\pm\\infty}$$<br/>$$\\frac{0}{0}$$<br/>$$\\pm\\infty\\cdot0$$<br/>$$0^0$$<br/>$$1^{\\pm\\infty}$$<br/>$$\\infty^{0}$$<br/>$$\\infty-\\infty$$"
}
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)=1$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)",
"steps": [
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}{c}=c$$",
"result": "=1"
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(3^{n+1}\\right)=\\infty\\:$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(3^{n+1}\\right)",
"steps": [
{
"type": "interim",
"title": "Apply exponent rules",
"input": "3^{n+1}",
"result": "=\\lim_{n\\to\\:\\infty\\:}\\left(e^{\\left(n+1\\right)\\ln\\left(3\\right)}\\right)",
"steps": [
{
"type": "step",
"primary": "Apply exponent rule: $$a^{x}=e^{\\ln\\left(a^{x}\\right)}$$",
"result": "=e^{\\ln\\left(3^{n+1}\\right)}",
"meta": {
"practiceLink": "/practice/exponent-practice",
"practiceTopic": "Expand FOIL"
}
},
{
"type": "step",
"primary": "Apply log rule: $$\\ln\\left(a^{x}\\right)=x\\cdot\\ln\\left(a\\right)$$",
"result": "=e^{\\left(n+1\\right)\\ln\\left(3\\right)}",
"meta": {
"practiceLink": "/practice/logarithms-practice",
"practiceTopic": "Expand FOIL"
}
}
],
"meta": {
"interimType": "Apply Exp Rules 0Eq"
}
},
{
"type": "interim",
"title": "Apply the Limit Chain Rule:$${\\quad}\\infty\\:$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(e^{\\left(n+1\\right)\\ln\\left(3\\right)}\\right)",
"steps": [
{
"type": "definition",
"title": "Limit Chain Rule",
"text": "if $$\\lim_{u\\:\\to\\:b}\\:f\\left(u\\right)=L,\\:$$and $$\\lim_{x\\:\\to\\:a}g\\left(x\\right)=b,\\:$$and $$f\\left(x\\right)\\:$$is continuous at $$x=b$$<br/>$$\\quad$$Then: $$\\lim_{x\\:\\to\\:a}\\:f\\left(g\\left(x\\right)\\right)=L$$",
"secondary": [
"$$g\\left(n\\right)=\\left(n+1\\right)\\ln\\left(3\\right),\\:f\\left(u\\right)=e^{u}$$"
]
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(\\left(n+1\\right)\\ln\\left(3\\right)\\right)=\\infty\\:$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(\\left(n+1\\right)\\ln\\left(3\\right)\\right)",
"steps": [
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}[c\\cdot{f\\left(x\\right)}]=c\\cdot\\lim_{x\\to{a}}{f\\left(x\\right)}$$",
"result": "=\\ln\\left(3\\right)\\cdot\\:\\lim_{n\\to\\:\\infty\\:}\\left(n+1\\right)"
},
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}[f\\left(x\\right)\\pm{g\\left(x\\right)}]=\\lim_{x\\to{a}}{f\\left(x\\right)}\\pm\\lim_{x\\to{a}}{g\\left(x\\right)}$$<br/>With the exception of indeterminate form",
"result": "=\\ln\\left(3\\right)\\left(\\lim_{n\\to\\:\\infty\\:}\\left(n\\right)+\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)\\right)",
"meta": {
"title": {
"extension": "Indeterminate Forms:<br/>$$\\frac{\\pm\\infty}{\\pm\\infty}$$<br/>$$\\frac{0}{0}$$<br/>$$\\pm\\infty\\cdot0$$<br/>$$0^0$$<br/>$$1^{\\pm\\infty}$$<br/>$$\\infty^{0}$$<br/>$$\\infty-\\infty$$"
}
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(n\\right)=\\infty\\:$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(n\\right)",
"steps": [
{
"type": "step",
"primary": "Apply the common limit: $$\\lim_{n\\to\\:\\infty\\:}\\left(n\\right)=\\infty\\:$$",
"result": "=\\infty\\:"
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)=1$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)",
"steps": [
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}{c}=c$$",
"result": "=1"
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "step",
"result": "=\\ln\\left(3\\right)\\left(\\infty\\:+1\\right)"
},
{
"type": "interim",
"title": "Simplify $$\\ln\\left(3\\right)\\left(\\infty\\:+1\\right):{\\quad}\\infty\\:$$",
"input": "\\ln\\left(3\\right)\\left(\\infty\\:+1\\right)",
"result": "=\\infty\\:",
"steps": [
{
"type": "interim",
"title": "$$\\infty\\:+1=\\infty\\:$$",
"input": "\\infty\\:+1",
"steps": [
{
"type": "step",
"primary": "Apply Infinity Property: $$\\infty\\:+c=\\infty\\:$$",
"result": "=\\infty\\:"
}
],
"meta": {
"interimType": "N/A"
}
},
{
"type": "step",
"result": "=\\ln\\left(3\\right)\\left(\\infty\\:\\right)"
},
{
"type": "interim",
"title": "$$\\ln\\left(3\\right)\\left(\\infty\\:\\right)=\\infty\\:$$",
"input": "\\ln\\left(3\\right)\\left(\\infty\\:\\right)",
"steps": [
{
"type": "step",
"primary": "Apply Infinity Property: $$c\\cdot\\infty=\\infty$$",
"result": "=\\infty\\:"
}
],
"meta": {
"interimType": "N/A"
}
},
{
"type": "step",
"result": "=\\infty\\:"
}
],
"meta": {
"solvingClass": "Solver",
"interimType": "Generic Simplify Specific 1Eq",
"gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7Yh4w7EfCxZSg4ozeO+skXBgUlp2a3w1QZHYsaqXCjTxwkKGJWEPFPk38sdJMsyPIwhWwQYyckKycWgIwD4f3sPC30sSftAIFS6Qkpy19IkqxSGm+I7f73Ci1MIDs4v5cqT2ATb/SVwJa8gQiZNBNYLCI2sSeA74029n2yo277ZU="
}
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "interim",
"title": "$$\\lim_{u\\to\\:\\infty\\:}\\left(e^{u}\\right)=\\infty\\:$$",
"input": "\\lim_{u\\to\\:\\infty\\:}\\left(e^{u}\\right)",
"steps": [
{
"type": "step",
"primary": "Apply the common limit: $$\\lim_{u\\to\\:\\infty\\:}\\left(e^{u}\\right)=\\infty\\:$$",
"result": "=\\infty\\:"
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "step",
"primary": "By the chain rule:",
"result": "=\\infty\\:"
}
],
"meta": {
"interimType": "Limit Chain Rule 0Eq",
"practiceLink": "/practice/limits-practice#area=main&subtopic=Chain%20Rule",
"practiceTopic": "Limit Chain Rule"
}
},
{
"type": "step",
"result": "=\\infty\\:"
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "step",
"result": "=2\\cdot\\:\\frac{1}{\\infty\\:}"
},
{
"type": "interim",
"title": "Simplify $$2\\cdot\\:\\frac{1}{\\infty\\:}:{\\quad}0$$",
"input": "2\\cdot\\:\\frac{1}{\\infty\\:}",
"result": "=0",
"steps": [
{
"type": "step",
"primary": "Apply Infinity Property: $$\\frac{c}{\\infty}=0$$",
"result": "=2\\cdot\\:0"
},
{
"type": "step",
"primary": "Apply rule $$0\\cdot\\:a=0$$",
"result": "=0"
}
],
"meta": {
"solvingClass": "Solver",
"interimType": "Generic Simplify Specific 1Eq",
"gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7/OsC643lXZbU+VEjF1qvioOn9HZuLHQfol+FkTFV5erehkKrn0era9rz8TlL+x/vZuJKdCFsPJy1+5gBMEc9doEFMST8lDZxn1Yq5HMKVTuF2Uk9xnPPKEGoObx02AbXJCTae4I8X+gaGFYzQzhr2qjWqX1f6iAOqMbShkzd9w0="
}
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "interim",
"title": "$$\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)=1$$",
"input": "\\lim_{n\\to\\:\\infty\\:}\\left(1\\right)",
"steps": [
{
"type": "step",
"primary": "$$\\lim_{x\\to{a}}{c}=c$$",
"result": "=1"
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "step",
"result": "=0+1"
},
{
"type": "step",
"primary": "Simplify",
"result": "=1",
"meta": {
"solvingClass": "Solver"
}
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "step",
"result": "=\\frac{\\frac{1}{3}}{1}"
},
{
"type": "step",
"primary": "Simplify",
"result": "=\\frac{1}{3}",
"meta": {
"solvingClass": "Solver"
}
}
],
"meta": {
"solvingClass": "Limits",
"interimType": "Limits"
}
},
{
"type": "step",
"primary": "$$L<1,\\:$$by the ratio test",
"result": "=\\mathrm{converges}"
}
],
"meta": {
"interimType": "Series Apply Ratio Test 0Eq"
}
},
{
"type": "step",
"result": "=5\\mathrm{converges}"
},
{
"type": "step",
"result": "=\\mathrm{converges}"
}
],
"meta": {
"solvingClass": "Series",
"practiceLink": "/practice/series-practice#area=main&subtopic=Ratio%20Test",
"practiceTopic": "Series Ratio Test"
}
}
}
Solution
Solution
Solution steps
Apply the constant multiplication rule:
Apply Series Ratio Test:converges
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Frequently Asked Questions (FAQ)
What is the sum from n=0 to infinity of 5/(2+3^n) ?
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