Given $$y = {{5x} \over {3\sqrt {{{\left( {1 - x} \right)}^2}} }} + {\cos ^2}\left( {2x + 1} \right)$$; Find $${{dy} \over {dx}}$$.
Answer
$${{dy} \over {dx}} = \left\{ {\matrix{
{{5 \over 3}.{1 \over {{{\left( {1 - x} \right)}^2}}} - 2\,\sin \left( {4x + 2} \right),} & {x < 1} \cr
{ - {5 \over 3}.{1 \over {{{\left( {x - 1} \right)}^2}}} - 2\,\sin \left( {4x + 2} \right),} & {x > 1} \cr
} } \right.$$
