Combine and .

Combine and .

Move to the left of .

Since is constant with respect to , the derivative of with respect to is .

Differentiate using the Power Rule which states that is where .

Combine and .

Multiply by .

Combine and .

Cancel the common factor of and .

Factor out of .

Cancel the common factors.

Factor out of .

Cancel the common factor.

Rewrite the expression.

Divide by .

Find the Derivative V(r)=4/3pir^3