DSolve[2*x*Sin[alpha]*y[x] + Cos[alpha]*(-x^2 + y[x]^2) + x*Sqrt[x^2 + y[x]^2] + (-2*x*Cos[alpha]*y[x] + Sin[alpha]*(-x^2 + y[x]^2) + y[x]*Sqrt[x^2 + y[x]^2])*Derivative[1][y][x] == 0,y[x],x]