# Integrate with power of e

Calculus Level 4

$\large{\displaystyle \int^{\infty}_{-\infty} \frac{e^{-6x}}{(1+e^{-2x})^{\frac{7}{2}}}dx=\frac{A}{B}}$

where $$A,B$$ are co prime positive integers.

Find $$B-A$$

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