Question

$\large \displaystyle \sf \int_{ - \infty }^{ \infty } \prod_{k = 1}^{ \infty} \cos \bigg( \frac{x}{ {2}^{k} } \bigg) \: dx$ ​

Answer 1

Answer:

$\huge \red\pi$

Step-by-step explanation:

I am living proof of definite integral ${sinx\over x}$ as it's well known .