00:01
Okay, so we're given our following u value, and we want to take the integral by using u sub.
00:08
So when we're using u sub, we also need to find du.
00:12
So that's equal to 4x to the power of 3, dx.
00:16
And notice here we have x in power 3, and we also have a dex here that i forgot to put it in.
00:22
Okay, so let's divide by this 4.
00:25
So we can have it in terms of our current integral.
00:31
Okay, and now let's replace our integral in terms of with now in terms of u.
00:37
So that is we get the integral of x cubed d x that's d u over four.
00:44
And then we have x4 plus 1, so that's now u.
00:48
So we have u to the power of negative 2 over 3...