Question

solve:

-sin^2x=2cosx-2

Answer 1

\[-(1-\cos^2x)=2cosx-2=> -1+\cos^2x-2cosx+2=0\]
\[=>\cos^2x-2cosx+1=0\]

Answer 2

\[=>(cosx-1)^2=0\]

Answer 3

\[cosx-1=0\]

Answer 4

\[cosx=1\]

Answer 5

\[x=2\pi n , n \in \mathbb{Z}\]

Answer 6

thanks!