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“what is the equation of a conic with vertices (-9,3) and (7,3) and foci (-5,3) and (3,3)”

User ERbittuu
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1 Answer

2 votes

This is an ellipse.

Equation of an ellipse:
(x^2)/(a^2)+(y^2)/(b^2)=1

Let's find the center point first. We can do this by finding out the midpoint between the vertices or the foci.

(-9+7)/2=-1

Center: (-1,3)

Now we need to find a and b (length along x and length along y).

We know "a". It is the distance between the center and the right or left bound.

a=7-(-1)=8

To find out "b", first see that...

b^2=a^2-(distance from center to foci)^2

foci distance=3-(-1)=4

b^2=8^2-4^2

b^2=64-16

b^2=48

b=4√3

answer:
((x+1)^2)/(64)+((y-3)^2)/(48)=1

User Christopher Clark
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