Question

Let T be the planar region enclosed by the square with vertices at the points (0,1), (1,0), (0, −1) and (−1,0). Then, the value of
$\iint\limits_T\left(\cos(\pi(x-y))-\cos(\pi(x+y))\right)^2dx\ dy$
equals ____________ (rounded off to two decimal places).

Answer 1

The correct answer is 1.95 to 2.05. (approx)