{
"query": {
"display": "foci $$y^{2}=-2x$$",
"symbolab_question": "CONIC#foci y^{2}=-2x"
},
"solution": {
"level": "PERFORMED",
"subject": "Geometry",
"topic": "Parabola",
"subTopic": "foci",
"default": "(-\\frac{1}{2},0)"
},
"steps": {
"type": "interim",
"title": "Parabola focus given $$y^{2}=-2x:{\\quad}\\left(-\\frac{1}{2},\\:0\\right)$$",
"steps": [
{
"type": "definition",
"title": "Parabola Focus",
"text": "A parabola is the locus of points such that the distance to a point (the focus) equals the distance to a line (the directrix)"
},
{
"type": "definition",
"title": "Parabola standard equation",
"text": "$$4p\\left(x-h\\right)=\\left(y-k\\right)^{2}\\:$$ is the standard equation for a right-left facing parabola with vertex at $$\\left(h,\\:k\\right),\\:$$<br/>and a focal length $$|p|$$"
},
{
"type": "interim",
"title": "Rewrite $$y^{2}=-2x\\:$$in the standard form:$${\\quad}4\\left(-\\frac{1}{2}\\right)\\left(x-0\\right)=\\left(y-0\\right)^{2}$$",
"input": "y^{2}=-2x",
"steps": [
{
"type": "step",
"primary": "Switch sides",
"result": "-2x=y^{2}"
},
{
"type": "step",
"primary": "Factor $$4$$",
"result": "4\\cdot\\:\\frac{-2}{4}x=y^{2}"
},
{
"type": "step",
"primary": "Simplify",
"result": "4\\left(-\\frac{1}{2}\\right)x=y^{2}"
},
{
"type": "step",
"primary": "Rewrite as",
"result": "4\\left(-\\frac{1}{2}\\right)\\left(x-0\\right)=\\left(y-0\\right)^{2}"
}
],
"meta": {
"interimType": "Parabola Canonical Format Title 1Eq",
"gptData": "pG0PljGlka7rWtIVHz2xymbOTBTIQkBEGSNjyYYsjjDErT97kX84sZPuiUzCW6s7aRgRQFW0MqhVT4GbzWEc4gPzfcrQwqpbdVOmllMsY7xeTXjeP8Fry4AS6VRPW/JxnSd9ckJvhaVSw11yD/KmDHfDBptXBowSMDY4Q9A3bJDasI5bAgvkB99F0ziQtvhJuX7fuMbxlCZKvOrjOW2rP/8//6/nV5O4fb8Xgwi7maqIP2TH9VLmoizBQwdUXcYE5AhrizZ3hCZ7G0NtzrdyrQMDmMFWkZD2KZqjQuE/LxJMyblZyz31NMRaqlLJV7CY"
}
},
{
"type": "step",
"result": "\\left(h,\\:k\\right)=\\left(0,\\:0\\right),\\:p=-\\frac{1}{2}"
},
{
"type": "step",
"primary": "Parabola is symmetric around the x-axis and so the focus lies a distance $$p$$ from the center $$\\left(0,\\:0\\right)$$ along the x-axis ",
"result": "\\left(0+p,\\:0\\right)"
},
{
"type": "step",
"result": "=\\left(0+\\left(-\\frac{1}{2}\\right),\\:0\\right)"
},
{
"type": "step",
"primary": "Refine",
"result": "\\left(-\\frac{1}{2},\\:0\\right)"
}
],
"meta": {
"solvingClass": "Parabola"
}
},
"plot_output": {
"meta": {
"plotInfo": {
"variable": "x",
"funcsToDraw": {
"funcs": [
{
"evalFormula": "y=\\sqrt{4(-\\frac{1}{2})x}+0",
"displayFormula": "4(-\\frac{1}{2})x=y^{2}",
"attributes": {
"color": "PURPLE",
"lineType": "NORMAL",
"isAsymptote": false
}
},
{
"evalFormula": "y=-\\sqrt{4(-\\frac{1}{2})x}+0",
"displayFormula": "4(-\\frac{1}{2})x=y^{2}",
"attributes": {
"color": "PURPLE",
"lineType": "NORMAL",
"isAsymptote": false
}
},
{
"evalFormula": "x=\\frac{1}{2}",
"displayFormula": "x=\\frac{1}{2}",
"attributes": {
"color": "GRAY",
"lineType": "NORMAL",
"labels": [
"\\mathrm{directrix}"
],
"isAsymptote": false
}
}
]
},
"pointsToDraw": {
"pointsLatex": [
"(0,0)",
"(-\\frac{1}{2},0)"
],
"pointsDecimal": [
{
"fst": 0,
"snd": 0
},
{
"fst": -0.5,
"snd": 0
}
],
"attributes": [
{
"color": "PURPLE",
"labels": [
"\\mathrm{vertex}"
],
"labelTypes": [
"DEFAULT"
],
"labelColors": [
"PURPLE"
]
},
{
"color": "PURPLE",
"labels": [
"\\mathrm{focus}"
],
"labelTypes": [
"DEFAULT"
],
"labelColors": [
"PURPLE"
]
}
]
},
"functionChanges": [
{
"origFormulaLatex": [],
"finalFormulaLatex": [],
"plotTitle": "4(-\\frac{1}{2})(x)=y^{2}",
"paramsLatex": [],
"paramsReplacementsLatex": []
}
],
"localBoundingBox": {
"xMin": -5.625,
"xMax": 5.625,
"yMin": -5.625,
"yMax": 5.625
}
},
"showViewLarger": true
}
}
}
Solution
foci
Solution
Solution steps
Rewrite in the standard form:
Parabola is symmetric around the x-axis and so the focus lies a distance from the center along the x-axis
Refine
Graph
Popular Examples
x^2+y^2-4x+10y+13=0x^2+y^2+2x+6y+2=0asymptotes of (y^2)/9-(x^2)/(16)=1asymptotes x=3y^2vertices 3y^2=24xvertices
Frequently Asked Questions (FAQ)
What is the foci y^2=-2x ?
The foci y^2=-2x is (-1/2 ,0)