f(x,y)=1/(xy); nn2<= X<=2; ln2<=y<=2ln2
the answer is shown in the attached file but i dont understand the circled value
thank you
The average of $\displaystyle f(x)$ on the interval $\displaystyle [a,b]$ is
$\displaystyle \frac{1}{b-a}\int_a^bf(x) \ dx$
The average of $\displaystyle f(x,y)$ on the square $\displaystyle [a,b] \times [c,d]$ is
$\displaystyle \frac{1}{(b-a)(d-c)}\int_c^d\int_a^bf(x,y) \ dx\ dy$