Use the change of variable formula evaluate the double integral ∫ ∫R 1/ (√1-x^2-y^2) dA where the region R is the part of the cartesian plane above the xaxis between the circles x^2+y^2=1 & x^2+y^2=4

Question

Can you please draw the region as well so that I can get more clarification

Answer 1

Imagine you have a perfectly shaped doughnut placed in the center of a x-y plane. Now only look at the top part of the graph, this is what we're looking for. The top arch is the circle of radius 2 and the bottom arch is the circle of radius 1. The space in between is region R.