# Why does this integral cut off the z component?

1. Jan 29, 2017

### grandpa2390

1. The problem statement, all variables and given/known data
Please don't make me post the entire question. If so, can I take a picture of the example in my textbook?

I am looking at an example in my textbook where we are to check Stoke's theorem

After doing the cross-product of del cross v I get (4z^2-2x)[x hat] + (2z^2)[z hat]
since da points in the x direction
da =dydz[x hat]
2. Relevant equations

integral of del cross v dot da
3. The attempt at a solution

when they do the integral, it is of the x component alone. why? is it because da is pointing in the x direction?

2. Jan 30, 2017

### BvU

You could at least divulge what C, S and F are (see here for nomenclature) (I suppose your da is his dS ?)

And $\ \hat x\$ reads a lot easier than [x hat]

3. Jan 30, 2017

### Ray Vickson

Yes.

4. Jan 30, 2017

thank you :)