00:01
Okay, so for this problem we're going to use the method in example 3 to find the slope of the curve at the given point and an equation for the tangent line.
00:10
We're using the method of slope or example 3.
00:14
So in example 3 they assume that there's a point q that makes a secant line with p.
00:20
Now remember a secant line is where you have two points on the curve and you connect them.
00:27
That's the secant line and we're going to define this point as 2 plus h comma this long expression here to the right.
00:37
And all i've done here is put substituted 2 plus h in for x in the expression.
00:42
So notice here 2 plus h cubed.
00:45
Notice here 2 plus h squared.
00:48
This is the y coordinate of the point q.
00:53
And so then we can use point p and point q.
00:59
We can find the slope of the secant line.
01:03
We do some substitution and the reason we get h is because your x coordinate is 2 plus h and then you subtract 2.
01:13
So you're left with h.
01:17
You'll notice i substituted this big y thing in first and then subtracted 0 to make it a little more painless.
01:26
And then i simplified this expression to have h squared plus 3h.
01:31
Now this is going to be give me the slope of the secant line.
01:35
So now if we're just thinking about what happens if we change h.
01:43
So if h is negative 1 then the slope of my secant line would be negative 2.
01:52
And so it's coming down...