If the area under the curve of f(x) = 25 - x^2 from x = -4 to x = 0 is estimated using four approximating rectangles and left endpoints, will the estimate be an underestimate or overestimate?


1) Underestimate

2) Overestimate

3) The area will be exact

4 answers

GRAPH IT(0at x=-5, 9 at x=-4, 25 at x=0
dy/dx = -2 x
d^2y/dx^2 =-2
This curve curves down (sheds water, d^2y/dx^2 <0 ) while the slope is positive for negative x
Therefore those rectangles do not fill the space under the curve.
In the given region, the graph is moving downwards.

Left endpoint approximation does not cover the entire region, and will hence give an underestimate.
thank you
It is not moving downwards. It is curving downwards :)