00:01
So, the thing with inverses is that you switch the x and y, so when they ask you to evaluate f inverse of 7, you can see what i'm going to do is just switch the 7 here and then the 3 here, and that's your first answer.
00:18
Now the second answer when they say to do f of f inverse of 10 is that the, essentially the f and the f inverse cancel out and you're just left with 10, which is actually what you want to do with the next problem, where they want you to verify that, well let me put down the theme as f of f inverse should just get you back to x.
00:45
So let me just go ahead and start with f inverse, which is 1 plus 2x over 1 minus x, and what i need to do is replace that with both x's in the f function, so i need to write that again, 1 plus, sorry, 1 minus x and 1 plus 2, x minus 1, x plus 2, alright, there we go, now i have it down right, 1 plus 2x over 1 minus x.
01:25
And what we can do is get the same denominator, that's at least how i would do that, so 1 plus 2x, and i also need to distribute this minus, so minus 1 plus x, now i have the same denominator, and same thing in this one, is 1 plus 2x, i need to distribute plus 2, so 2 times 1 is 2 minus 2x, all over 1 minus x...