\[ \cos (x) y'(x)-y(x)^4-y(x) \sin (x)=0 \] ✓ Mathematica : cpu = 0.121139 (sec), leaf count = 98
DSolve[-(Sin[x]*y[x]) - y[x]^4 + Cos[x]*Derivative[1][y][x] == 0,y[x],x]
\[\left \{\left \{y(x)\to \frac {1}{\sqrt [3]{-\sin (x)+c_1 \cos ^3(x)-2 \sin (x) \cos ^2(x)}}\right \},\left \{y(x)\to -\frac {\sqrt [3]{-1}}{\sqrt [3]{-\sin (x)+c_1 \cos ^3(x)-2 \sin (x) \cos ^2(x)}}\right \},\left \{y(x)\to \frac {(-1)^{2/3}}{\sqrt [3]{-\sin (x)+c_1 \cos ^3(x)-2 \sin (x) \cos ^2(x)}}\right \}\right \}\] ✓ Maple : cpu = 0.123 (sec), leaf count = 237
dsolve(cos(x)*diff(y(x),x)-y(x)^4-y(x)*sin(x) = 0,y(x))
\[y \left (x \right ) = \frac {\left (\cos \left (x \right ) \left (c_{1} \left (\sin ^{4}\left (x \right )\right )+2 \cos \left (x \right ) \left (\sin ^{3}\left (x \right )\right )-2 c_{1} \left (\sin ^{2}\left (x \right )\right )-3 \sin \left (x \right ) \cos \left (x \right )+c_{1}\right )^{2}\right )^{\frac {1}{3}}}{c_{1} \left (\sin ^{4}\left (x \right )\right )+2 \cos \left (x \right ) \left (\sin ^{3}\left (x \right )\right )-2 c_{1} \left (\sin ^{2}\left (x \right )\right )-3 \sin \left (x \right ) \cos \left (x \right )+c_{1}}\]