Calculate ∫0∞x2ex−1dx\int_0^{\infty} \frac{x^2}{e^x-1} dx∫0∞ex−1x2dx.
2ζ(3)2\zeta(3)2ζ(3)
ζ(3)\zeta(3)ζ(3)
π2/6\pi^2/6π2/6
π4/15\pi^4/15π4/15