00:02
Okay, this i want to integrate using parts, and i'll make this item the u and this item the dv idx.
00:11
So, u times v is the first item.
00:16
So we have ln, cosine x, no change there.
00:21
And to find v, i integrate sinex.
00:24
Integrate sinex, the answer is negative.
00:27
Cosine x.
00:30
Again, reverse differentiation.
00:31
Differentiate cosine, i get negative sign.
00:36
That's how it works.
00:37
Minus the integral of, do it down here, the same thing, minus cosine x, times du by dx, differentiate ln, cos x.
00:50
On the bottom is cos x.
00:53
On the top is minus sinex.
00:56
Differentiate cause.
00:57
I get negative sign by the chain rule, dx...