0;\\
\cosx=\sin x;\\
tgx=1;\\
x=\frac\pi4+\pi n,\ n\in Z" alt="\sin2x-2\sin^2x=4\sin x-4\cos x;\\
2\sin x\cos x-2\sin^2x=4\sin x-4\cos x;\\
\sin x\cos x-\sin^2x=2\sin x-2\cos x;\\
\cos x\cdot(\sin x+2)=\sin x\cdot(\sin x+2);\\
\forall x:\ \ \sin x>0;\\
\cosx=\sin x;\\
tgx=1;\\
x=\frac\pi4+\pi n,\ n\in Z" align="absmiddle" class="latex-formula">