00:01
For this question, we are given a function f of x and we're also given a graph of the function.
00:08
Now first, we need to write an integral that represents the length of this curve.
00:14
You can see that we're already given the limits of integration, negative 2 to 6, since this is the domain of the function represented in the graph.
00:24
From here, we need to write the integrand.
00:27
To do this, use the formula that says that the length.
00:30
Length of the curve is equal to the integral from a to b of the square root of 1 plus f prime of x squared dx.
00:46
So we have already been given a and b, which are going to be negative 2 and 6.
00:52
So all we're missing is f prime of x.
00:55
To find f prime of x, first recall that f of x is equal to 4 plus 5 cosine x.
01:04
So to find f prime of x, we just need to take the derivative, which we can do term by term.
01:12
Start by taking the derivative of 4.
01:14
So the derivative of a constant is always 0.
01:18
So the derivative of 4 is just 0...