Algebra Examples

Graph x^2=4y
x2=4yx2=4y
Step 1
Solve for yy.
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Step 1.1
Rewrite the equation as 4y=x24y=x2.
4y=x24y=x2
Step 1.2
Divide each term in 4y=x24y=x2 by 44 and simplify.
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Step 1.2.1
Divide each term in 4y=x24y=x2 by 44.
4y4=x244y4=x24
Step 1.2.2
Simplify the left side.
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Step 1.2.2.1
Cancel the common factor of 44.
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Step 1.2.2.1.1
Cancel the common factor.
4y4=x244y4=x24
Step 1.2.2.1.2
Divide yy by 11.
y=x24y=x24
y=x24y=x24
y=x24y=x24
y=x24y=x24
y=x24y=x24
Step 2
Find the properties of the given parabola.
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Step 2.1
Rewrite the equation in vertex form.
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Step 2.1.1
Complete the square for x24x24.
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Step 2.1.1.1
Use the form ax2+bx+cax2+bx+c, to find the values of aa, bb, and cc.
a=14a=14
b=0b=0
c=0c=0
Step 2.1.1.2
Consider the vertex form of a parabola.
a(x+d)2+ea(x+d)2+e
Step 2.1.1.3
Find the value of dd using the formula d=b2ad=b2a.
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Step 2.1.1.3.1
Substitute the values of aa and bb into the formula d=b2ad=b2a.
d=02(14)d=02(14)
Step 2.1.1.3.2
Simplify the right side.
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Step 2.1.1.3.2.1
Cancel the common factor of 00 and 22.
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Step 2.1.1.3.2.1.1
Factor 22 out of 00.
d=2(0)2(14)d=2(0)2(14)
Step 2.1.1.3.2.1.2
Cancel the common factors.
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Step 2.1.1.3.2.1.2.1
Cancel the common factor.
d=202(14)d=202(14)
Step 2.1.1.3.2.1.2.2
Rewrite the expression.
d=014d=014
d=014d=014
d=014d=014
Step 2.1.1.3.2.2
Multiply the numerator by the reciprocal of the denominator.
d=04d=04
Step 2.1.1.3.2.3
Multiply 00 by 44.
d=0d=0
d=0d=0
d=0d=0
Step 2.1.1.4
Find the value of ee using the formula e=c-b24ae=cb24a.
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Step 2.1.1.4.1
Substitute the values of cc, bb and aa into the formula e=c-b24ae=cb24a.
e=0-024(14)e=0024(14)
Step 2.1.1.4.2
Simplify the right side.
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Step 2.1.1.4.2.1
Simplify each term.
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Step 2.1.1.4.2.1.1
Raising 00 to any positive power yields 00.
e=0-04(14)e=004(14)
Step 2.1.1.4.2.1.2
Combine 44 and 1414.
e=0-044e=0044
Step 2.1.1.4.2.1.3
Divide 44 by 44.
e=0-01e=001
Step 2.1.1.4.2.1.4
Divide 00 by 11.
e=0-0e=00
Step 2.1.1.4.2.1.5
Multiply -11 by 00.
e=0+0e=0+0
e=0+0e=0+0
Step 2.1.1.4.2.2
Add 00 and 00.
e=0e=0
e=0e=0
e=0e=0
Step 2.1.1.5
Substitute the values of aa, dd, and ee into the vertex form 14x214x2.
14x214x2
14x214x2
Step 2.1.2
Set yy equal to the new right side.
y=14x2y=14x2
y=14x2y=14x2
Step 2.2
Use the vertex form, y=a(x-h)2+ky=a(xh)2+k, to determine the values of aa, hh, and kk.
a=14a=14
h=0h=0
k=0k=0
Step 2.3
Since the value of aa is positive, the parabola opens up.
Opens Up
Step 2.4
Find the vertex (h,k)(h,k).
(0,0)(0,0)
Step 2.5
Find pp, the distance from the vertex to the focus.
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Step 2.5.1
Find the distance from the vertex to a focus of the parabola by using the following formula.
14a14a
Step 2.5.2
Substitute the value of aa into the formula.
14141414
Step 2.5.3
Simplify.
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Step 2.5.3.1
Combine 44 and 1414.
144144
Step 2.5.3.2
Simplify by dividing numbers.
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Step 2.5.3.2.1
Divide 44 by 44.
1111
Step 2.5.3.2.2
Divide 11 by 11.
11
11
11
11
Step 2.6
Find the focus.
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Step 2.6.1
The focus of a parabola can be found by adding pp to the y-coordinate kk if the parabola opens up or down.
(h,k+p)(h,k+p)
Step 2.6.2
Substitute the known values of hh, pp, and kk into the formula and simplify.
(0,1)(0,1)
(0,1)(0,1)
Step 2.7
Find the axis of symmetry by finding the line that passes through the vertex and the focus.
x=0x=0
Step 2.8
Find the directrix.
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Step 2.8.1
The directrix of a parabola is the horizontal line found by subtracting pp from the y-coordinate kk of the vertex if the parabola opens up or down.
y=k-py=kp
Step 2.8.2
Substitute the known values of pp and kk into the formula and simplify.
y=-1y=1
y=-1y=1
Step 2.9
Use the properties of the parabola to analyze and graph the parabola.
Direction: Opens Up
Vertex: (0,0)(0,0)
Focus: (0,1)(0,1)
Axis of Symmetry: x=0x=0
Directrix: y=-1y=1
Direction: Opens Up
Vertex: (0,0)(0,0)
Focus: (0,1)(0,1)
Axis of Symmetry: x=0x=0
Directrix: y=-1y=1
Step 3
Select a few xx values, and plug them into the equation to find the corresponding yy values. The xx values should be selected around the vertex.
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Step 3.1
Replace the variable xx with -22 in the expression.
f(-2)=(-2)24f(2)=(2)24
Step 3.2
Simplify the result.
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Step 3.2.1
Raise -22 to the power of 22.
f(-2)=44f(2)=44
Step 3.2.2
Divide 44 by 44.
f(-2)=1f(2)=1
Step 3.2.3
The final answer is 11.
11
11
Step 3.3
The yy value at x=-2x=2 is 11.
y=1y=1
Step 3.4
Replace the variable xx with -11 in the expression.
f(-1)=(-1)24f(1)=(1)24
Step 3.5
Simplify the result.
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Step 3.5.1
Raise -11 to the power of 22.
f(-1)=14f(1)=14
Step 3.5.2
The final answer is 1414.
1414
1414
Step 3.6
The yy value at x=-1x=1 is 1414.
y=14y=14
Step 3.7
Replace the variable xx with 22 in the expression.
f(2)=(2)24f(2)=(2)24
Step 3.8
Simplify the result.
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Step 3.8.1
Raise 22 to the power of 22.
f(2)=44f(2)=44
Step 3.8.2
Divide 44 by 44.
f(2)=1f(2)=1
Step 3.8.3
The final answer is 11.
11
11
Step 3.9
The yy value at x=2x=2 is 11.
y=1y=1
Step 3.10
Replace the variable xx with 11 in the expression.
f(1)=(1)24f(1)=(1)24
Step 3.11
Simplify the result.
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Step 3.11.1
One to any power is one.
f(1)=14f(1)=14
Step 3.11.2
The final answer is 1414.
1414
1414
Step 3.12
The yy value at x=1x=1 is 1414.
y=14y=14
Step 3.13
Graph the parabola using its properties and the selected points.
xy-21-1140011421xy211140011421
xy-21-1140011421
Step 4
Graph the parabola using its properties and the selected points.
Direction: Opens Up
Vertex: (0,0)
Focus: (0,1)
Axis of Symmetry: x=0
Directrix: y=-1
xy-21-1140011421
Step 5
image of graph
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