integration by parts? 2 variables Expected value.

168 Views Asked by At

Can someone please give some detail on the blue square steps? Thank you in advance. enter image description here

1

There are 1 best solutions below

2
On

$$ \int_0^{d} \dfrac{2y(d-y)}{d^2} dy = \dfrac{1}{d^2} \int_0^{d} \left(2dy-2y^2\right) dy = \dfrac{1}{d^2} [dy^2-\dfrac{2}{3}y^3]_0^d = \dfrac{d}{3}. $$