Wikipediapartial(f,s)
Returns the partial derivative of function f with respect to the argument name in variable s.
See also derivative totalderivative jacobian gradient divergence curl
Example
V(r,h)=pi*r^2*h/3
V(r,h)=pi*r^2*h/3
Vr=partial(V,"r")
Vr(r, h) = 2/3*h*pi*r