ODE No. 820

\[ y'(x)=\frac {\csc (y(x)) \left (\frac {1}{2} x^2 \log (x) \cos (2 y(x))+\frac {1}{2} x^2 \log (x)-\cos (y(x))\right )}{x \log (x)} \] Mathematica : cpu = 0.499912 (sec), leaf count = 63

DSolve[Derivative[1][y][x] == (Csc[y[x]]*(-Cos[y[x]] + (x^2*Log[x])/2 + (x^2*Cos[2*y[x]]*Log[x])/2))/(x*Log[x]),y[x],x]
 

\[\left \{\left \{y(x)\to -\sec ^{-1}\left (\frac {-x^2+2 x^2 \log (x)-4 c_1}{4 \log (x)}\right )\right \},\left \{y(x)\to \sec ^{-1}\left (\frac {-x^2+2 x^2 \log (x)-4 c_1}{4 \log (x)}\right )\right \}\right \}\] Maple : cpu = 0.874 (sec), leaf count = 27

dsolve(diff(y(x),x) = 1/2*(-2*cos(y(x))+x^2*cos(2*y(x))*ln(x)+x^2*ln(x))/sin(y(x))/ln(x)/x,y(x))
 

\[y \left (x \right ) = \arccos \left (\frac {4 \ln \left (x \right )}{2 x^{2} \ln \left (x \right )-x^{2}+4 c_{1}}\right )\]