Chapter 4.3, Problem 68E

Evaluate the limit by first recognizing the sum as a Riemann sum for a function defined on [0, 1].

$\underset{n\to \infty }{\lim }\frac{1}{n}\left(\sqrt{\frac{1}{n}}+\sqrt{\frac{2}{n}}+\sqrt{\frac{3}{n}}+\mathrm{...}+\sqrt{\frac{n}{n}}\right)$