00:01
So on this question, we're going to look at finding the average rate of change when the interval is or when the function is cotangent of t.
00:09
And for the first interval, let's take a look at going from pi over four to three pi over four.
00:16
So the average rate of change going from pi over four to three pi over four.
00:24
For average rate of change, we want to use f of b minus f of a over b minus a.
00:31
In this case, we're working with a function h.
00:34
So you can just change that to h of b and h of a.
00:39
And then b and a are the end points on the interval.
00:43
So in this case, h of b is h of 3 pi over 4, minus h of pi over 4.
00:51
And then i'm going from b to a.
00:53
So minus on the denominator, 3 pi over 4, minus pi over 4.
00:59
So now let's take a look at some of those values.
01:02
So h of 3 pi over 4 is cotangent at 3 pi over 4.
01:06
Remember that's where sign and cosine are the same, but they have opposite sign.
01:11
So that's a negative 1.
01:13
And then h of pi over 4 is cotangent of pi over 4, and that's where they are equal to 1, where sign and cosine are equal.
01:20
And then on the denominator, you're going to have 3 pi minus 1 pi, which makes it 2 pi over 4...