# HELP: Integral

1. Dec 8, 2008

### BobSun

Limit of an integral
1. The problem statement, all variables and given/known data
Evaluate:
the limit as n goes to $$\infty$$ of
$$\int^{1}_{0} (n^{3/2}x^{5/4})/(1+n^{2}x^{2})dx$$
dx is the lebesgue measure

2. Relevant equations
I thought I could use the monotone convergence theorem or the dominated convergence theorem neither work.

3. The attempt at a solution
the intregrand is dominated by $$1/\sqrt{x}$$ but $$1/\sqrt{x}$$ isn't lebesgue integrable.

2. Dec 8, 2008

### HallsofIvy

Staff Emeritus
?? $1/\sqrt{x}= x^{-1/2}$ surely is Lebesque integrable on [0,1]. In fact, it is Riemann integrable and its integral from 0 to 1 is just $\left 2x^{1/2}\right|_{x=0}^1= 2$.