This is my exercise in Complex Analysis.
$$ \int_0^\infty \left(\frac{\sin x}{x}\right)^2\,dx = ? $$
I tried solving this by $(\sin x)^2=1-\cos(2x)$ but I realized that $\int_0^\infty \frac{dx}{x^2}$ does not converge.
Can someone help me? Thank you so much.