00:01
So what they ask you to do is take tangent squared, which is what f of x is named as in g of x, which is secant squared, and take the derivative of each of those.
00:19
Well, the derivative of this would be the chain rule where you bring the two in front, tangent of x, and then the derivative of tangent is secant squared of x, and do the same thing with g.
00:32
So that's another chain rule.
00:35
You bring the two in front, leave sikin of x alone, and then multiplied by the derivative of secant, which is secant x tangent x.
00:46
And what you notice from that is that f prime of x is equal to g prime of x.
00:59
Another way of saying that is that g prime of x, and you can flip this around.
01:11
If you really want to, minus f prime of x is equal to zero...