đk: \(\sin x\ne0\Leftrightarrow x\ne k\pi\)
pt \(\Leftrightarrow\sin^2x+\sin x.\cos x=1=\sin^2x+\cos^2x\)
\(\Leftrightarrow\sin x.\cos x-\cos^2x=0\)
\(\Leftrightarrow\left[{}\begin{matrix}\cos x=0\\\cos x=\sin x\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{\pi}{2}+k\pi\\x=\pm\dfrac{\pi}{4}+k2\pi\end{matrix}\right.\)(thoả mãn)