Posted by Adrianna on Tuesday, March 20, 2012 at 12:40pm.
x = rcosθ y = rsinθ x^2 - y^2 = r^2 cos^2 θ - r^2 sin^2 θ = r^2(cos^2 θ - sin^2 θ) = r^2 cos2θ so, we have r^2 cos2θ = 16 r^2 = 16/cos2θ
Thank you.