We know that : $$a \times b = \underbrace{a + a + a + ... + a}_{\text{b times}}$$
That's how we convert from a product to a sum.
So what happens if we go a little further?
That is : $$\prod\limits_{a}^{b} {f(x)} = \sum\limits_{?}^{?} {?}$$
$$\text{where } b>a$$
What will be in the place of those $'?'$
So if $f(x) = \sin{(x)} \text{ or } = x^3 \text{ or } = a^x$ or something like that?
Or what if $b=\infty$ ?
I guess this is a silly question but please help! Thanks!