00:01
So we're given the function f of x is equal to 6 divided by x plus 1.
00:06
And what we want to do is we want to find the slope of the tangent line to the graph of f at 2 comma 2.
00:12
That's where we want to find it.
00:13
And so how do we do it? well, basically that means we want to find f prime of 2, the derivative of the function at x equals 2.
00:22
And so we want to do this using the limit definition because that's how the chapter in the book wants us to do it.
00:27
And so, so to find the derivative of a function at a point using the limit definition, that's going to be the limit as x approaches a of f of x minus f of a divided by x minus a.
00:45
And so f prime of 2 is equal to the limit as x approaches 2 of f of x minus f of 2 divided by x minus 2.
00:56
And so now what i can do is i can scroll down and then we can do some substituting and all that.
01:07
So f prime of 2 is equal to the limit as x approaches to of well, our f of x is just our function.
01:15
So 6 over x plus 1 minus f of 2.
01:19
Well, if our f of x is 6 over x plus 1, then our f of 2 is going to be 6 over 3 or 2.
01:25
2.
01:26
So minus 2, i think i did it right.
01:29
Yeah, minus 2 divided by x minus 2.
01:32
And so f prime of 2 is equal to the limit as x approaches 2 of, we can simplify this, get common denominator.
01:43
So we're going to get 6 over x plus 1 minus 2 times x plus 1 divided by x plus 1 all over x minus 2...