sec^2 x cos x + cos x - 2 = 0
How do you do this?? Merci pour votre aide!
+129845 sec^2 x cos x + cos x - 2 = 0
(1/cos^2x)*cosx + cosx - 2 = 0
1/cosx + cosx - 2 = 0 multiply through by cos x
1 + cos^2x - 2cosx = 0 rearrange
cos^2 x - 2cos^2x + 1 = 0 factor
(cosx -1) (cosx - 1) = 0 and since the factors are the same, we can solve for just one of them
cosx - 1 = 0 add 1 to both sides
cosx = 1 so, x = 0 ± n*360° where n is just an integer
