Find the partial derivative fxf_xfx of the function f(x,y)=xln(x+y)f(x,y) = x \ln(x + y)f(x,y)=xln(x+y).
ln(x+y)+xx+y\ln(x+y) + \frac{x}{x+y}ln(x+y)+x+yx
ln(x+y)\ln(x+y)ln(x+y)
xx+y\frac{x}{x+y}x+yx
ln(x+y)+1x+y\ln(x+y) + \frac{1}{x+y}ln(x+y)+x+y1