The bottom limit is beta and the top limit is y the function is 1/x^(alpha +1) dx
$\displaystyle \int_\beta^y \frac{1}{x^{\alpha+1}} dx$ =$\displaystyle \int_\beta^y x^{-\alpha-1} dx$ =$\displaystyle -\frac{x^{-\alpha}}{\alpha+1} |_{x=\beta}^y$ =$\displaystyle -\frac{y^{-\alpha}}{\alpha+1}+\frac{\beta^{-\alpha}}{\alpha+1}$=$\displaystyle \frac{\beta^{-\alpha}-y^{-\alpha}}{\alpha+1}$=$\displaystyle \frac{y^\alpha-\beta^\alpha}{(\alpha+1)(y\beta)^\alpha}$