00:01
Let's find the derivative of this function, evaluated at x equals 4, using the table in the book.
00:05
Now, unfortunately, i can't put the table on my whiteboard, but we can still discuss it and find the answer.
00:11
So starting off, we're just going to take the derivative of this function.
00:14
You'll notice that there is division, meaning we have the quotient rule, as well as multiplication, meaning we have the product rule.
00:20
Let's begin.
00:22
So we have, for the quotient rule, the bottom times derivative of the top.
00:26
So that's x times, well, derivative at the top is product rule.
00:31
First, f of x times derivative of second, g prime of x, plus second, g of x times derivative first, f prime of x.
00:42
All right, so that was derivative of the top.
00:45
Then we subtract top times derivative bottom, that is f of x times g of x, times derivative of x, which is one, all divided by the bottom squared, x squared, and all of this is still evaluated at x equals four.
01:03
It's a pretty long equation now.
01:06
So anyways, let's simplify this a little bit...