Why am I getting different signs for these triple integrals?

[-EquinoX-]

Homework Statement

http://img5.imageshack.us/img5/6596/67023499.th.jpg

http://img5.imageshack.us/img5/3875/13930604.jpg

Homework Equations

The Attempt at a Solution

my answer to the first one is negative and the second one is positive, is this correct?

 

[yyat]

Regarding (b): What happens when you split the integral into the part where x>0 and the part where x<0, how are they related?

 

[HallsofIvy]

(a) is pretty simple isn't it? $z\le 1$ so $z^2- z$is what?

For (b) use "symmetry" as yyat suggests.

 

[-EquinoX-]

so a is negative and b is 0?

 

[yyat]

so a is negative and b is 0?

Yes.

 

[-EquinoX-]

thanks