Question

use an iterated integral to find area of region bounded by graphs sin(x) and cos(x) between x=pi/4 and x=5*pi/4 but using HORIZONTAL strips.(i.e dxdy is order of integration for the double integral). it has been suggested by a textbook that this is a formidable task.

easy enough when order of integration is dydx using vertical strips to get 2*sqrt(2).