How can I prove that these integrals do not converge?

47 Views Asked by At

Can you please help me to prove the integrals \begin{equation*} \int_0^\pi \frac{x}{\sin(x)}~\text{and}~\int_0^\infty \frac{1}{\sqrt{x}}\cos(x^{-1}) \end{equation*} are divergent? Please I really need it.

Thank you.

1

There are 1 best solutions below

0
On

Hint:

  • the first : When $x \to \pi$, we have $\sin x = \sin (\pi -x) \sim \pi - x$ and $\int_1^{\pi} \frac{\pi}{\pi -x}$ diverges.