00:01
We are asked to find the inverse's derivative at the c value of pi.
00:12
So what we have first is the function is defined as 2x plus cosine of x, and there's got to be some bound.
00:27
Oh, maybe not.
00:31
I guess we don't really need bounds on this.
00:36
And the reason for that is when you take the derivative, well, the derivative of 2x is 2.
00:42
The derivative of cosine is negative sign.
00:45
And this is always positive because sine of x is always between negative 1 and 1.
00:53
No matter what you do, you're going to get an answer between negative 1 and 1.
00:56
And when you add 2 to that, the result is going to be between 1 and 3.
01:04
So yes, it is true that this function is always positive.
01:09
The derivative is positive, so f is increasing everywhere...