Decide, without calculation, if each of the integrals below are positive, negative, or zero. Let D be the region inside the unit circle centered at the origin. Let T, B, R, and L denote the regions enclosed by the top half, the bottom half, the right half, and the left half of unit circle, respectively.
1. $\iint_R xe^x dA$
2. $\iint_L xe^x dA$
3. $\iint_B xe^x dA$
4. $\iint_D xe^x dA$
5. $\iint_T xe^x dA$