The general solution of $ 2 \cos 4x + \sin^2 2x $= 0 is
The expression $ \frac{2 \tan A}{1 - \cot A} + \frac{2 \cot A}{1 - \tan A} $ can be written as
If $ \cos A = m \cos B $ and $ \cot \left( \frac{A+B}{2} \right) = \lambda \tan \left( \frac{B-A}{2} \right), $ then $ \lambda \text{ is equal to} $