00:01
We are going to locate our relative extrema using the second derivative test, if possible.
00:07
So let's first examine the derivative from the product rule.
00:12
First times the derivative of the second.
00:16
The derivative of an e to the u is e to the u, du.
00:19
So it would be e to the negative x times negative 1, plus the second term times the derivative of the first, which is 2x.
00:31
We could rewrite that as negative x squared over e to the x plus 2x over e to the x or negative x squared plus 2x over e to the x critical numbers could come when the second derivative is non -differentiable but that's not going to happen because the bottom cannot be zero or it can come when the derivative is zero.
01:04
And fractions are zero when the top or numerator is zero.
01:11
To find where that's zero, let's factor out a negative x, which is going to give us the solutions of x equals zero and x equals two.
01:26
Now let's see what sign the second derivative is at that point...