# Homework Help: Using Dirichlet's test for uniform convergence

1. Apr 26, 2010

### cchatham

1. The problem statement, all variables and given/known data
Show that $$\sum$$(-1)^(n+1) / (n + x^2) converges uniformly but not absolutely on R.

2. Relevant equations
Using Dirichlet's Test for uniform convergence. (fn) and (gn) are sequences of functions on D satisfying:
$$\sum$$ fn has uniformly bounded partial sums
gn -> 0 uniformly on D
g(n+1)(x) $$\leq$$ gn(x) for all x in D and all n in N

3. The attempt at a solution
I got parts a) and c) down since obviously (-1)^(n+1) is uniformly bounded by 1 and 1 / (n+1+x^2) < 1 / (n + x^2) for all x in R and all n in N. I'm having trouble showing that 1 / (n+x^2) is uniformly convergent on R. I tried using Weierstrass' M-test but can't seem to make that work.