# Math Help - Riemann's sum question

1. ## Riemann's sum question

Express the integral as a limit of Riemann sums. Do not evaluate the limit.

Answer I got for this is...

(2+5/ni) - 3ln(2+5/ni) * 5/n.

I thought it was right, but apparently it's wrong.

2. Originally Posted by Jgirl689
Express the integral as a limit of Riemann sums. Do not evaluate the limit.

Answer I got for this is...

(2+5/ni) - 3ln(2+5/ni) * 5/n.

I thought it was right, but apparently it's wrong.

As the function in the integral is continuous is $[2,7]$ we know the integral exists and thus we can choose the partition of the interval as we want. We choose

to subdivide $[2,7]$ in n subintervals of equal length $\frac{7-2}{n}=\frac{5}{n}$ , and we evaluate the function at right end of each subinterval:

$\lim_{n\to\infty}\sum^n_{i=i}\frac{5}{n}\left[2+\frac{5i}{n}-3\ln\left(2+\frac{5i}{n}\right)\right]$ ...this looks similar to what you got but I can't be sure since it isn't clear the way you wrote it.

Tonio