00:01
So we're given this function, k of x, and in part of our question, we're going to try and find the derivative of k at negative 1.
00:10
And so the first thing we're going to do is find the derivative of k of x, which we're going to use the power rule to find.
00:17
And so what we do with the power rule is we look at our exponent.
00:20
And this time, in this case, we have x to the 3.
00:23
We bring down that exponent, and then we minus 1 to our exponent.
00:27
So we take this 3, and we put it out front.
00:30
And then we have times x squared, and then we do the same with this x.
00:34
So we just have x to the first, so we bring down a 1 times x to the 0th, which is also 1.
00:40
So our derivative is 3x squared minus 1.
00:43
And if you're wondering about what we do with this constant here, negative 1, for all derivatives, we let constants go to 0 when we look at the derivative.
00:51
When we find a derivative, all constants go to 0.
00:56
So now we can just plug in negative 1...