00:01
Hello everyone.
00:02
So today we've got some information at the top of the page here, and we're going to use that to help sketch a graph of the function f.
00:09
So before i sketch the real graph, i always like to make a little number line just to organize what's going on on the x axis before we bother with what the y values look like.
00:20
So we can sort of split this information into like an f prime and f double prime section here.
00:26
So on f prime, it's pretty simple just from looking at it here.
00:33
At x equals 5 on our axis, maybe we go like 0, 1, 2, 3, 4, 5, 6, 7, 8, because i see 8 here, so maybe something like this.
00:47
At x equals 5, the derivative is 0.
00:54
But before that, it seems that f prime is less than zero.
01:03
So it would be decreasing before x equals 5 and increasing after it.
01:13
So there's some behavior that we have already.
01:17
Now when we look at the second derivative, we should get some info on when our function is concave up and concave down.
01:24
Now we see that at x equals 2 and x equals 8, that the second derivative is 0, which means it's probably an inflection point, because that's when our second derivative would change from positive to negative.
01:39
So let's see here...