How do you solve sin^2 x = 2cosx + 2sin2x=2cosx+2 from 0 to 2pi?

1 Answer
May 7, 2018

color(purple)(=> piπ

Explanation:

sin^2x = 2 cos x + 2sin2x=2cosx+2

1 - cos^2 x = 2 cos x + 21cos2x=2cosx+2

cos^2 x + 2 cos x + 2 - 1 = 0cos2x+2cosx+21=0

cos^2 x + 2 cos x + 1 = 0cos2x+2cosx+1=0

(cos x = 1)^2 = 0(cosx=1)2=0

cos x + 1 = 0cosx+1=0

cos x = -1 cosx=1

color(purple)(x = cos ^-1 -1 = cos^-1 cos (pi) = pix=cos11=cos1cos(π)=π