\input epsf
\nopagenumbers
\magnification=\magstep1

\noindent {\bf Problem statement} Suppose that $f(x,y)$ is some
function of two variables and we wish to evaluate
$\displaystyle I=\int\!\int_Rf(x,y)\,dA$, where $R$ is the region in the $xy$-plane
lying between the circles $x^2+y^2=4$ and $(x-1)^2+y^2=1$. Set up (but
do not try to evaluate) $I$ as a sum of iterated integrals.
 
\vfil\eject\end