Find all the partial derivatives of g(x,y,z) = (x) /(x+y) .
a) gx = y/(x+y) ², gy = -x/(x+y) ², gz = 0
b) gx = 1/(x+y) , gy = -x/(x+y) ², gz = 0
c) gx = y/(x+y) ², gy = -1/(x+y) ², gz = 0
d) gx = 1/(x+y) , gy = -1/(x+y) ², gz = 0