# How would you do it? Part 2

Calculus Level 5

Let $S=\sum_{r=1}^{\infty} \int_{-\infty}^{\infty}\frac{dx}{x^2-2^{(2^{(r+1)})}x+3^r}$

Then find, $$S^3+9S+27$$

Note: Work with the Cauchy principal value of the integrals.

If you're looking for another challenge in calculus, try this

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