00:01
Let's find the inverse of this function.
00:03
Let's change f of x to y.
00:08
Now, let's switch x and y.
00:18
Okay, so we need to remove the fraction.
00:21
So we're going to multiply both sides of the equation by the least common denominator, y minus 3.
00:33
And that's going to give me this.
00:37
We'll distribute.
00:42
And last, we want to get both the ys on one side and both the x is on the other side.
00:51
So just remember if they switch sides, they're going to change signs.
00:56
We'll factor the y out of the left -hand side, and we'll finish by dividing both sides by x minus 2.
01:11
Now, remember that x cannot equal 2, and let's also revert back to the function notation, using this notation right here for the inverse for our final answer.
01:29
Now, to test them, we're going to do the composition of functions.
01:37
And this is where the math gets a little bit difficult.
01:41
We're going to start by doing f of the inverse of x.
01:47
So that means we're starting with the inverse function.
01:52
And everywhere that we have an x, we're going to replace that x with the original function.
02:00
So it's going to be three times.
02:05
2x plus 1 over x minus 3, the original function, plus 1.
02:12
And instead of saying 1, i'm going to call 1 x minus 3 over x minus 3.
02:18
I'm going to go ahead and get those common denominators now.
02:22
So on the bottom, instead of x minus 2, we have the original function substituted in for x.
02:31
And instead of minus 2, we're going to do this.
02:37
So again, we have those common denominators.
02:41
And hopefully you can see that that's still equivalent to 2.
02:45
Right, now, let's go ahead and rate those as single fractions with common denominators of x minus 3...