How to find area? will give..

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

Given that y varies directly to the square root of (x + 1), and that y = 1 when x = 8,(a)express y in terms of .x,(b)find the value of y when x = 3,(c)find the value of x when y = 5.

Use the squared identities to simplify sin^2x cos^2x