CPM Homework Help : APCALC Problem 2-84

Write a Riemann sum for a general function $f$ to estimate the area under the curve for $2\le x\le5$ using $n$ left endpoint rectangles of equal width if:

$n = 3$ rectangles

$n = 9$ rectangles

$n = 300$ rectangles

Hint:

General form of left-endpoint Riemann Sum:

$\displaystyle \sum_{i=0}^{n-1}\Delta xf(a+\Delta xi)$

$n$ represents number of rectangles.
$a$ represents starting value on the $x$ -axis.
$b$ represents ending value on the $x$ -axis.

$\Delta x\text{ represents width of each rectangle}:\frac{b-a}{n}$