Consider the area shown below. The curve drawn is $x^2 + y^2 = 5$, and we have used the notation $Dy$ for $\Delta y$.

Write a Riemann sum for the area, using the strip shown:
Riemann sum $= \Sigma$

Now write an integral that gives this area
$\int_a^b\,$
where $a =$ and $b =$

Finally, calculate the exact area of the region, using your integral
area =