\[ \left (y'(x)^2+1\right ) \sin ^2\left (y(x)-x y'(x)\right )-1=0 \] ✓ Mathematica : cpu = 0.0443811 (sec), leaf count = 59
\[\left \{\left \{y(x)\to c_1 x-\frac {1}{2} \cos ^{-1}\left (\frac {c_1^2-1}{c_1^2+1}\right )\right \},\left \{y(x)\to c_1 x+\frac {1}{2} \cos ^{-1}\left (\frac {c_1^2-1}{c_1^2+1}\right )\right \}\right \}\]
✓ Maple : cpu = 1.012 (sec), leaf count = 147
\[ \left \{ y \left ( x \right ) =x{\it \_C1}-\arcsin \left ( {\frac {1}{\sqrt {{{\it \_C1}}^{2}+1}}} \right ) ,y \left ( x \right ) =x{\it \_C1}+\arcsin \left ( {\frac {1}{\sqrt {{{\it \_C1}}^{2}+1}}} \right ) ,y \left ( x \right ) =-x\sqrt {{x}^{-1}}\sqrt {1-x}-\arcsin \left ( \sqrt {{x}^{-1}}x \right ) ,y \left ( x \right ) =x\sqrt {{x}^{-1}}\sqrt {1-x}+\arcsin \left ( \sqrt {{x}^{-1}}x \right ) ,y \left ( x \right ) =-x\sqrt {-{x}^{-1}}\sqrt {1+x}-\arcsin \left ( \sqrt {-{x}^{-1}}x \right ) ,y \left ( x \right ) =x\sqrt {-{x}^{-1}}\sqrt {1+x}+\arcsin \left ( \sqrt {-{x}^{-1}}x \right ) \right \} \]