N
nhocxomkeo


$\begin{array}{l}
\frac{{{{\sin }^4}x + {{\cos }^4}x + {{\sin }^2}2x}}{{1 - \cos 2x}} - {\cot ^2}2x.\cos 2x = \frac{{1 + \cos 2x}}{2} + {\cot ^2}2x \\
\\
\end{array}$
mong thầy giúp em
\frac{{{{\sin }^4}x + {{\cos }^4}x + {{\sin }^2}2x}}{{1 - \cos 2x}} - {\cot ^2}2x.\cos 2x = \frac{{1 + \cos 2x}}{2} + {\cot ^2}2x \\
\\
\end{array}$
mong thầy giúp em