00:01
This is problem 24 from 8 .4.
00:04
And now we have a definite interval that looks like this.
00:08
And because of the denominator that has squared of 4 minus x squared, we can, we know we're, we know that we want to make either one of this x equals 2 times cosine or 2 times sine a substitution.
00:26
Well, both of them will work just fine.
00:29
So i'll just go with x equals sine t.
00:32
Now, since we have a definite interval, we need to figure out the balance and be careful about that.
00:38
So we have x going from 0 to 1.
00:41
So that means sine of t will be going from 0 to 1 half.
00:49
And so that means since sine is an increasing function on its, from 0 to pi, we can deduce that this is, 0 and t.
01:05
And what is the value of t that gives one half? well, that is pi over 6.
01:11
So we can parameterize x as this sign of function, that's sine of t.
01:19
And let's compute what's 4 minus x squared is.
01:24
What it's going to be, after substitution, it's going to be 4 times cosine squared of t...