\[ \boxed { \sin \left ( x \right ) {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) - \left ( y \left ( x \right ) \right ) ^{2} \left ( \sin \left ( x \right ) \right ) ^{2}+ \left ( \cos \left ( x \right ) -3\,\sin \left ( x \right ) \right ) y \left ( x \right ) +4=0} \]
Mathematica: cpu = 0.057507 (sec), leaf count = 27 \[ \left \{\left \{y(x)\to \frac {\csc (x)}{c_1 e^{5 x}+\frac {1}{5}}-4 \csc (x)\right \}\right \} \]
Maple: cpu = 0.093 (sec), leaf count = 28 \[ \left \{ y \left ( x \right ) =-4\,{\frac { \left ( {{\rm e}^{x}} \right ) ^{5}{\it \_C1}+1}{\sin \left ( x \right ) \left ( \left ( { {\rm e}^{x}} \right ) ^{5}{\it \_C1}-4 \right ) }} \right \} \]