nice-calculus-for-f-x-f-x-pi-f-x-sin-2-x-x-2-dx-why-0-pi-f-x-dx-

Question Number 136835 by mnjuly1970 last updated on 26/Mar/21

\dots . . n i c e c a l c u l u s \dots

f o r f (x) = f (x + π) :

\int_{- \infty}^{\infty} f (x) . \frac{{s i n}^{2} (x)}{x^{2}} d x \overset{w h y ? ? ?}{=} \int_{0}^{π} f (x) d x