Question

How do I get x^2-y^2 into polar coordinates?

Answer 1

x^2+y^2=r^2 so x^2-y^2=-r^2

Answer 2

Ooh wow.. that was so simple it was hard. Okay thank you! haha

Answer 3

you are welcome. just multiply both sides by negative one

Answer 4

\(\bf \color{blue}{x= rcos(\theta)\qquad y = rsin(\theta)}\\ \quad \\
x^2-y^2\implies [rcos(\theta)]^2-[rsin(\theta)]^2\implies [r^2cos^2(\theta)]^2-[r^2sin^2(\theta)]\\ \quad \\
r^2[cos^2(\theta)-sin^2(\theta)]\implies r^2[cos(2\theta)]\)

Answer 5

how does it equal \[\cos (2\theta)\]

Answer 6

it is r^2(cos(2theta))

cos^2(x) - sin^2(x) = cos(2x)

Answer 7

trig id:

jag was not right btw

Answer 8

Yay i got it right! Thanks :)

Answer 9

woops i thought it was -x^2-y^2. sorry