precal
posted by Lynn on .
sin^2x/cosx=sec^2x1

sin^2x /cosx = 1/cos^2 x  1
multiply each side by cos^2 x
sin^2 x cosx = 1  cos^2x
(1  cos^2x)cosx = 1  cos^2x
cosx  cos^3x  1 + cos^2x = 0
cos^3x  cos^2x  cosx + 1 = 0
cos^2x(cosx  1) (cosx  1) = 0
(cosx1)(cos^2x1) =0
(cosx1)(cosx1)(cosx+1) = 0
cosx = 1 or cosx = 1
x = 0, 2π or x = π