$int(1/(a^2+x^2))dx$

A cura di: Francesco Speciale

Svolgimento:
$int(1/(a^2+x^2))dx=int(1/(a^2[1+(x/a)^2]))dx=1/aint(1/(1+(x/a)^2)D(x/a))dx=1/aarctg(x/a)+c$.