Method for finding the potiential fuction f(x,y, z) given the gradient vector field F = < fx, fy, fz>:
1) Evaluate f(x,y,z) = S fx dx = g(x,y,z) + C₁(y,z),
      where C₁(x,y) represents terms not containing x.
2) Evaluate f(x,y,z) = S fy dy = h(x,y,z) + C₂(x,z),
       where C₂(x,z) represents terms not containing y.
3) Evaluate f(x,y,z) = S fz dz = k(x,y,z) + C₃(x,y),
       where C₃(x,y) represents terms not containing z.
4) f(x,y,z) = g(x,y,z) + (sum of terms in h(x,y,z) not listed in g(x,y,z)) + (sum of terms in not listed in g(x,y,z) or h(x,y,z)) + K,
       where K is a constant

Proof of method: