00:01
So we're looking at f of x defined as 1 over x plus 3.
00:05
Our interval is going from negative 1 to 4.
00:08
And we want n equaling 4 in this problem.
00:11
So what we need to figure out is the width, or the delta x, in the problem, which is going to be your upper bound minus your lower bound divided by the number of rectangles.
00:21
So you end up with 5 divided by 4, or 1 .25.
00:26
And at this point, then, i like to make a table to figure out what my y values are starting at negative 1.
00:34
And i'm going up by 1 .25.
00:37
So my next x value would be 0 .25, and then 1 .5, and then 2 .75.
00:44
And i'll end at 4, which is a good thing.
00:48
So now what i have to do is plug in these values in here.
00:52
And sometimes they're really easy, like that's just 1 half.
00:56
But then this would be 1 over 3 .25 when i add.
01:01
Plugging in 1 .5 gives me 1 over 4 .5.
01:05
And then 2 .75, adding 3 to that would be 1 over 5 .75.
01:10
And then 1 seventh.
01:12
So now they want you to do the right sum of those four.
01:16
Now each width is 1 .25...