Question

Convert the Cartesian equation x^4 - y^4 = 16 to a polar equation?

r^2 = 16/cos2θ
r^4 = 16/cos2θ
r^2 = 8

Answer 1

so far i have
r^4(cos^4(theta)-sin^4(theta))=16

Answer 2

Do you know any trig identities to simplify that?

Answer 3

I think the answer is B, but i'm not totally sure

Answer 4

I don't know I just learned this today and my worksheet doesn't say anything about it.

Answer 5

But I think your right.

Answer 6

Thank you

Answer 7

I think it simplifies to cos(2x)(1)

Answer 8

r^4cos(2x)=16
r^4=16/cos(2x)

Answer 9

Ok thanks!

Answer 10

https://www.youtube.com/watch?v=JSBUnq535vM

Answer 11

that explains the identity

Answer 12

no problem