00:01
All right, so we're told that the function f of x is equal to 7 over x, so a hyperbolic function.
00:09
And we want to find the equation of the c -camp line from x equals 4 to x equals 7.
00:17
So if x is equal to 4, then f of x, we just plug in 4, is going to be 7 over 4.
00:24
And then at x equal to 7, f of 7 is equal to 3.
00:30
7 over 7, which is just 1.
00:34
So if we want to find the secan line, we take the y values, or f of 7 minus f of 4 for the slope, and then we divide by the x values.
00:47
So the rise over the run.
00:50
So we get 1 minus 7 over 4 divided by 3.
00:55
This is 4 over 4 minus 7 of 4.
00:57
So it's negative 3 over 4 divided by 3.
01:02
So that's just going to be negative 1 over 4.
01:05
Negative 1 4th is the slope of our secant line.
01:08
And then we can write it in slope form.
01:10
We know that y minus y1 is equal to m times x minus x1.
01:15
Let's use the point 7 comma 1 because there's, i don't want to deal with the fraction 7 over 4.
01:21
You could use either point and you'll get the same simplified equation.
01:25
So y minus 1, the y value here, is equal to the calculated slope negative 1 4th times x, minus the x value for that point is seven.
01:35
Then we can distribute the negative one -fourth.
01:38
I'm just getting it in slope intercept form.
01:41
So this is plus.
01:42
Oh, look at that...