\[ \boxed { {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) = \left ( y \left ( x \right ) +\cos \left ( x \right ) \right ) ^{2}+\sin \left ( x \right ) =0} \]
Mathematica: cpu = 0.029004 (sec), leaf count = 18 \[ \left \{\left \{y(x)\to \frac {1}{c_1-x}-\cos (x)\right \}\right \} \]
Maple: cpu = 0.047 (sec), leaf count = 16 \[ \left \{ y \left ( x \right ) =-\cos \left ( x \right ) + \left ( {\it \_C1 }-x \right ) ^{-1} \right \} \]