sin(y)cos(x)-π²/4=sin(x+y)-y²+x. Assuming dy/dx is required:
-sin(y)sin(x)+cos(y)cos(x)dy/dx=cos(x+y)(1+dy/dx)-2ydy/dx+1 is the implicit derivative from which:
cos(y)cos(x)dy/dx-cos(x+y)dy/dx+2ydy/dx=sin(y)sin(x)+cos(x+y)+1.
Therefore, dy/dx=(sin(y)sin(x)+cos(x+y)+1)/(cos(y)cos(x)-cos(x+y)+2y).