00:01
This question will given the function kx equal to 4x divided by 3x2x2x2 plus 27 and you know to answer those questions in the here we need to find the k prime x here and here we apply the product the question rule and then we should get the 3x square plus 27 square the derivative of the numerator equal to 4 with the denominator here, no minus the derivative of the denominator equal to the 6x times with the 4x.
00:42
And if we simplify the numerator, we have the 12x2 plus 27 times 4, equal to 108 minus 24 x squared divided by 3x square plus 27 square and then we have this one equal to 1 0 .8 minus 12 x square over the 3x square plus 27 power 2.
01:15
And now we need to find the critical numbers.
01:19
We need to set this one equal to 0.
01:21
And just even only if 12 x square must equal to 108, even only if x square must equal to 108, even only if x square must equal equals equal to 1 or 8 divided by 12.
01:31
So we should get dividing by 12 and we get equal to 9.
01:37
Isn't even only if x equals to plus and minus 3.
01:42
And because we are considered the x here is a number of hours, so we don't consider the minus here.
01:49
So we just need to worry about the plus now...