00:01
For this problem, we are asked to find the critical numbers of f of x equals x to power of 5 minus 5x all over 5 is the first part of the problem.
00:08
So we can do this by writing this as f prime of x equals 1 over 5 times d by d x of x of x of 5 minus 5x.
00:18
So this would then be 1 over 5 times derivative of x power 5 is 5x to the power of 4, and the derivative of 5x is just going to be 5.
00:29
Then we divide all of that by five, so we get x to the power of 4 minus 1.
00:36
Then, to find the critical numbers, we need to find when x the power of 4 equals 1, which will be the case when x equals plus or minus 1.
00:46
So we have two critical numbers.
00:48
I'll also note that for x the power of 4 minus 1, or actually for our expanded out version, or actually just generally speaking what we have here, can see that it is an awesome, power function or an odd order.
01:06
The word's not coming to me, but it has a odd highest power.
01:11
Word almost came to me.
01:13
Nope.
01:13
It's not happening...