00:01
Okay, so this is a standardized test question, and we're asked, does this function cross the x -axis between x -equals 1 and x -equals 2? now, seriously, if i were doing this on a standardized test, i would probably just graph it, and i would see.
00:22
But this could be the portion of a test where you don't have a graphing calculator.
00:28
So if i didn't have it, then i would put in x equals 1 and x equals 2, and i would see what this evaluates 2.
00:41
So when x equals 1, then the function is x to the third power minus x to the second power minus 2.
00:51
But i'm putting in 1 where x used to be.
00:55
So i'm going to raise these xs.
01:00
I'm going to write parentheses because we really should put parentheses in as placeholders where variables used to be.
01:09
And then i'm going to put one in there.
01:12
All right.
01:13
One to the third power is one minus one to the second power, which is also one.
01:26
So one minus one is zero and zero minus two is negative two.
01:32
So f of 1 is negative 2.
01:39
Okay, let's get f of 2...