Question

2cos^2x+cosx=cos2x

Answer 1

Wrong subject bro

Answer 2

Nvm

Answer 3

Da other guy in da wrong subject

Answer 4

\[2\cos ^2x+\cos x=\cos 2x\]
\[2\cos^2x+\cos x=\cos ^2x-\sin ^2x=\cos ^2x-(1-\cos ^2x)=2\cos ^2x-1,\cos x=-1\]
\[\cos x=-1=\cos( \pi+2k \pi),x=(2k+1)\pi,where~k ~is~an~integer.\]

Answer 5

Thank you!

Answer 6

yw