Added December 20, 2018.
PDE solved by Laplace transform. Solve for \(u(x,y)\) \[ u_{xy} = \sin (x) \sin (y) \] With boundary conditions \begin {align*} u(x,0)&=1+\cos (x) \\ \frac {\partial u}{\partial y}(0,y) &= -2 \sin y \end {align*}
Mathematica ✓
ClearAll["Global`*"]; pde = D[u[x, y], y, x] == Sin[x]*Sin[y]; bc = {u[x, 0] == 1 + Cos[x], Derivative[0, 1][u][0, y] == -2*Sin[y]}; sol = AbsoluteTiming[TimeConstrained[DSolve[{pde, bc}, u[x, y], x, y], 60*10]];
\[\{\{u(x,y)\to (\cos (x)+1) \cos (y)\}\}\]
Maple ✓
restart; pde := diff(u(x, y), y,x)=sin(x)*sin(y); bc := u(x,0)=1+cos(x),eval( diff(u(x,y),y),x=0)=-2*sin(y); cpu_time := timelimit(60*10,CodeTools[Usage](assign('sol',pdsolve([pde, bc],u(x,y))),output='realtime'));
\[u \left (x , y\right ) = \left (\cos \left (x \right )+1\right ) \cos \left (y \right )\]
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