Approximate the area under the graph of f(x) and above the x-axis using n rectangles.
f(x)=3x^2-2 from x=1 to x=5; n=4; use the right endpoints
Hello plstevens,
$\displaystyle \int_{a}^{b}f(x)dx \approx \sum_{n=1}^{4}f(x_n)\Delta x$
Where $\displaystyle \Delta x =\frac{b-a}{n}=\frac{5-1}{4}=1$ and
$\displaystyle x_n=a+n \Delta x =1+n\Delta x \mbox{ for } n=1,2,3,4$
Plugging into the above formula we get
$\displaystyle \int_{a}^{b}f(x)dx \approx \sum_{n=1}^{4}f(x_n)\Delta x=f(2)+f(3)+f(4)+f(5)$
It is all down hillfrom here.
Good luck