4cos^2 x - cosx-3 =0

Question

0 to 2pi

SORRY TYPED THE QUESTION WRONG PLESSE HELP

Answer 1

let cosx = t, then your equation becomes

4t^2 - t - 3 = 0
(4t + 3)(t - 1) = 0
t= -3/4 or t = 1

cosx = -3/4 or cosx = 1

now follow the steps I used for your previous post when you were Sara

http://www.jiskha.com/display.cgi?id=1490924093