Question

How do you estimate the area under the graph of `f(x)=3cos(x)` from the interval where x is between [0,2] using four rectangles and the right end points?

Answer 1

For `x` between `0` and `2`, part of the graph is under the `x` axis. The question is not clear.

graph{y=3cos(x) [-1.973, 7.89, -1.66, 3.273]}