00:01
Find f inverse prime of 1 if f of x is the cosine of 2x.
00:07
Okay, so here's the domain of f, and here's the range of f.
00:18
So f takes things from here, usually called x, sends them over here to things called y, usually.
00:27
And then f inverse comes along and takes this y and sends it back to this x.
00:33
That was f, this is f inverse.
00:36
So this set over here, that's the range of f, is now the domain of f inverse.
00:43
And it sends it over here back to the same set that x came from, which is the range now of f inverse.
00:53
Okay, so there's x, f changes it to y, and then f inverse changes it back to x again.
01:01
Or there's y, f inverse changes it to x, and then f changes it back to y again...