Question

Please help with a pre calc question. I will fan and medal best response.

Answer 1

@satellite73

Answer 2

@ganeshie8

Answer 3

The equation of an ellipse centered at the origin is
\[\frac{ x^2 }{ a^2}+\frac{ y^2 }{ b^2 }=1\]
We know three points (0, 58), (21, 29), and (-21,29). If you substitute the points you should be able to solve for a and b.

Answer 4

So:
((21^2)/a^2) +((29^2)/b^2) = 1?

Answer 5

not really following you here... sorry

Answer 6

yes that's right. And if you use (0,58) you can eliminate the x² part, which allows you to solve for b

Answer 7

I'm sorry but can you just show me the steps with the information. Once I've done it once, it will make sense but right now I just don't get it.

Answer 8

@Loser66 can you help?

Answer 9

\[\frac{ 0^2 }{ a^2 }+\frac{ 58^2 }{ b^2 }=1\]
\[\frac{ 58^2 }{ b^2 }=1\]
Now you can solve for b

Answer 10

wouldn't that mean that b=58?

Answer 11

yes.

Answer 12

oh ok. lol so how about finding a

Answer 13

now put 58 into the equation you made above.
\[\frac{ 21^2 }{ a^2 }+\frac{ 29^2 }{ 58^2 }=1\]

Answer 14

now I just plug in a different pair of coordinates with b = 58?

Answer 15

ok got it that all i need thanks

Answer 16

you're welcome

Answer 17

@peachpi
sorry dude I thought I could get through the rest of the problem by myself but I got stuck can you help me finish it?

Answer 18

@Loser66 can you help me finish the problem?

Answer 19

I got this far:
First find b from:
(0^2/a^2) + (58^2/b^2) = 1
58^2/b^2 = 1
b = 58

Now find a:
(21^2/a^2) + (29^2/58^2) = 1
(21^2/a^2) + 1/4 = 1
(21^2/a^2) = 3/4 or 0.75

Answer 20

@peachpi please finish it. I didn't follow the stuff.

Answer 21

he went offline