00:01
All right, so for this problem, we're going to find a derivative of sine of x times cosine of 1 minus x squared.
00:07
Okay.
00:08
So, first thing to notice, we've got sine of x, right, times cosine of 1 minus x squared.
00:17
Okay, so this is going to be a product rule.
00:20
So product rule, f is our first thing, so f is sine of x.
00:27
G is our second thing.
00:29
G is cosine of 1 minus x.
00:33
X squared okay and we need f and f prime and g prime right so f prime all right well the derivative sine of x is cosine of x we need g prime all right well this we've got cosine of of of all right well this we've got cosine of and then some more complicated stuff inside okay so we've got a sort of inside part we need to worry about complicated inside part we've got an outside part okay so for this, we're going to have to use chain rule.
01:03
All right.
01:04
So let's look up here.
01:05
Chain rule means we take the derivative of the outside part and just plug in the inside part.
01:13
And then we multiply by the derivative of the inside part.
01:17
So what this means is, well, our outside part was the cosine.
01:21
So cosine of u is our outside part.
01:25
So if we take the derivative of cosine u, we get negative sine u, we get negative sign.
01:31
U.
01:32
Okay, but we're gonna plug in g of x.
01:34
So we're gonna and excuse me, i say we're gonna plug in g of x, but our gs here are different.
01:40
This is not the same of x.
01:41
We're gonna plug in our inside.
01:43
Okay, we're gonna plug in our inside.
01:44
Okay, and leave our inside the same.
01:45
So negative sign of one minus x squared...