1: TXĐ: x>=0
2: ĐKXĐ: \(\sin x< >\cos x\)
\(\Leftrightarrow\sin x< >\sin\left(\dfrac{\Pi}{2}-x\right)\)
\(\Leftrightarrow\left\{{}\begin{matrix}x< >\dfrac{\Pi}{2}-x+k2\Pi\\x< >\dfrac{\Pi}{2}+x+k2\Pi\end{matrix}\right.\Leftrightarrow2x< >\dfrac{\Pi}{2}+k2\Pi\)
hay \(x\ne\dfrac{\Pi}{4}+k\Pi\)