00:01
We have a function x squared from x to 0 to x to 1, and we want to estimate the area that's trapped underneath it first by breaking this into two rectangles and then into four.
00:14
And we want to do this by drawing the rectangles whose midpoints are hitting the curve.
00:23
So in the first problem where we're going to let n equal 2, we want to draw two rectangles, and if we divide it into two regions, since it's going from 0 to 1, then the regions are each one half wide.
00:42
Since we want the midpoints of the rectangles to hit, we want to go halfway in between their start and finish on the x -axis to hit.
00:50
So the first rectangle is going to hit halfway from 0 to 1 half, which is a fourth.
00:57
The second one's going to hit halfway from a half to 1, which is three -fourths.
01:03
Each of the rectangles are one half wide.
01:07
The area of the first rectangle is one half times its height, and its height is when x is one -fourth.
01:16
If we fill one -fourth in for x and f of x, that would give us one -sixteenth, one -fourth squared.
01:25
Second rectangle, also a half wide.
01:28
For its height, that occurs when x is three -fourths, and if we fill that in for x squared, that's nine -sixteenths.
01:37
That will give us one -thirty -second plus nine -thirty -seconds, or ten -thirty -seconds, which reduces to five -sixteenths as our estimation...