Homework Statement
Show that the function f : [0,1] × [0,1] → R given by
f(x,y) =
{ 0 if x is irrational, or x is rational and y is irrational
{ 1/q if x is rational, y = p/q with gcd(p,q) = 1
Is integrable and compute the integral.
Homework Equations
The Attempt at a...