00:01
In this problem, we are given a function f equal to 2 times x to power 3 halves, from which we want to find its arc length, starting from the point 0 .00.
00:13
Generally speaking, an arc length s is equal to the integral from starting point a to ending point b of the square root of 1 plus d .f over dx squared dx.
00:33
So in our case, we are starting from point a is equal to 0, and ending on an arbitrary point b is equal to x.
00:40
And to evaluate this integral, we're first going to have to evaluate the derivative of f.
00:46
Let's calculate that right away.
00:48
D .f over dx will give us two times three halves x to the one -half, simplifying to three times x to the one -half.
01:07
Now let's square this quantity because in our integrant we have the f over the x squared and this will give us 9 times x.
01:19
So now our arc length s that we want to evaluate between a is equal to 0 and b is equal to x will give us the integral 1 plus 9x, the square root of 1 plus 9x, dx.
01:41
Now to evaluate this integral, we're going to post -change of variable that u is equal to 1 plus 9x.
01:52
We then will have that the u is equal to 9 times d x.
01:57
Now our integral, we're right to the integral from u, evaluate at x equal to 0, to u devalued at x, and we are going to integrate the square root of you.
02:13
Times d u over 9...