00:01
So let's draw our curve.
00:03
We have y is equal to sine inverse of x, which means x is equal to sine of y.
00:13
And then we have our line, y is equal to pi over four.
00:20
So this is the region that we want to find the volume four.
00:24
So we would have our r, lowercase r, which would be equal to x.
00:30
So volume is equal to integral from 0 to pi over 4 r squared t y or v is equal to there's a pi in there as well so v is equal to integral from 0 to pi over 4 pi times x squared d y we can put this pi in front of the integral so v is equal to pi times the integral from 0 to pi over 4 and x is equal to sine y so sine y squared d y or we have b is equal to pi times the integral from 0 2 pi over 4 sine squared of y d y now on a side note we have cosine of 2 y is equal to 1 minus sine squared, 1 minus 2, sine squared of y.
01:39
So we can write this as cosine 2y, cosine 2y minus 1 is equal to negative 2 sine squared y.
01:55
Or 1 minus cosine 2 y is equal to 2 sine squared y.
02:03
So we can then say 1 over 2 minus cosine 2 y over 2 is equal to sine square of y.
02:17
So that's the substitution that we're going to make here as we integrate this...