00:01
Okay, so for this problem, we can first write out the first order derivative and the second of the derivative, which we will use later.
00:12
So the first order directive is this, and the second order directive is 2 times long of x plus 3.
00:25
So first, for the increasing and decrease interval, we just set the first of the derivative equals to 0.
00:31
That gives us x equals to e to d minus one half.
00:38
Be careful, we don't think x equals to zero is a solution because the domain of if is from zero to infinity.
00:53
Zero is excluded.
00:56
So we only have one solution for this equation and which separates this domain to two sub -intervals.
01:05
So from 0 to e to the minus 1 1 half, and from e to the minus 1 half to infinity.
01:14
And we can see that on the first interval, the first of the derivative is negative...