definite integral answer different from Riemann Sum calc

Hi everybody,

I have to calculate a definite integral using the oh so necessary Riemann Sum.

I first calculated the integral with the fundamental theorem as a check.

The integral is from 1 to 2 of (2+3x^2)dx and it equals 9 according to my calculation.

When I calculated with tv Riemann sum, it equaled 1, so I must have made a mistake.

I started by finding delta x = 1/n and xi = i/n

then I set up the equation to be:

lim of n->inf Sigma i=1 to n of f(i/n) 1/n

Isn't that correct?

I then solved it and got 1 as the answer.

If anybody could help me out that would be great.

Thx