# 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

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.