# Strange Integral- Does it even exist?

1. Jul 25, 2008

### The_ArtofScience

I was watching DonnyLee's videos on youtube and I noticed something strange. I think he picked u=x and du=dx, and if I'm right (?) he picked v= $$\int x dy/dx$$ but does that even equal to y? But that can't be right because the right side kept the original expression. Some help might clear up the fuzziness

https://www.youtube.com/watch?v=<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/GAkkTa2XpEc&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><embed src="http://www.youtube.com/v/GAkkTa2XpEc&hl=en&fs=1" type="application/x-shockwave-flash" allowfullscreen="true" width="425" height="344"></embed></object>

2. Jul 25, 2008

### spideyunlimit

can't see any video.... give the link

3. Jul 25, 2008

### The_ArtofScience

4. Jul 25, 2008

### matticus

I believe:

u = y. du = dy/dx * dx.
dv = d/dx* x * dx. v = x.