# It's a product? Not a sum?

Calculus Level 4

$\large \displaystyle \lim_{n \to \infty} \prod_{r=3}^{n} \dfrac{r^3 - 2^3}{r^3 + 2^3}$

If the above limit can be expressed in the form $$\dfrac{a}{b}$$ where $$a$$ and $$b$$ are coprime positive integers, find the value of $$a+b$$.

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