math
posted by Gigi .
convert to polar form:
1) x^2y^2=4 (You may leave your answer for this one as r2 =)
2) x^2+(y1)^2=1

we know
r^2 = x^2 + y^2
x/r = cosØ, and y/r = sinØ or x=rcosØ and y = rsinØ
x^2  y^2 = 4
r^2 cos^2 Ø  r^2 sin^2Ø = 4
r^2 (cos^2 Ø  sin^2 Ø) = 4
r^2 (cos 2Ø)=4
r^2 = 4/cos 2Ø or r^2 = 4sec 2Ø
follow the same procedure for the second one, let me know what you got 
how did you get cos 2Ø after subtracting cos^2Øsin^2Ø?

One of the basic trig identities says:
cos 2A = cos^2 A  sin^2 A