Originally Posted by
tonio 1.- $\displaystyle \int\limits_1^4\int\limits_1^2 \frac{x}{y}+\frac{y}{x}\;dy\,dx=\int\limits_1^4dx\ left(\int\limits_1^2\left(\frac{x}{y}+\frac{y}{x}\ right)dy\right)=\int\limits_1^4dx\left(x\ln y+\frac{1}{2x}y^2\right)_1^2$
Well, I did the first one now you do the second one AFTER plugging in the limits (for y!) in the primitive function we got above. You get two nice, not hard integrals in x.
Try to walk now your way with problem 2 and if you get stuck somewhere in the way write back AFTER you do some work on it.
Tonio