Product rule works with ∂ as "boundary operator"

2. Product Rule of Calculus
Or written using the
“special D” for derivative
rather than “prime”:

3. Product Rule of Calculus
For example:

4. Surface Area
of a cylinder
I can never remember the formula

5. The “special d”
also means “boundary”

6. The “special d”
also means “boundary”

7. The “special d”
also means “boundary”

8. The product rule of
as “derivative”
works also with
as “boundary”

10. Volume of a cylinder

11. Surface area
of a cylinder
Surface area Volume

12. Surface area
of a cylinder
(top & bottom) “paper towel roll” side