Hi all,

there are two circles, one is bigger than the other, and overlapping a bit, I want to know could Julia help to calculate the bigger circle shaded area? Maybe this is geometry problem. But it is on Calculus book.

This is the solution:

I am using Latex to draw it, I canβt hardly plot it with Julia, too difficult:

```
\documentclass[12pt]{article}
\usepackage{tikz}
\usetikzlibrary{decorations.pathreplacing}
\usetikzlibrary {calc}
\newcommand{\MarkRightAngle}[4][.3cm]% #1=size (optional), #2-#4 three points: \angle #2#3#4
{\coordinate (tempa) at ($(#3)!#1!(#2)$);
\coordinate (tempb) at ($(#3)!#1!(#4)$);
\coordinate (tempc) at ($(tempa)!0.5!(tempb)$);%midpoint
\draw (tempa) -- ($(#3)!2!(tempc)$) -- (tempb);
}
\begin{document}
\begin{tikzpicture}[scale=1,>=latex,x=1cm,y=0.8cm]
\draw[fill=blue!7] (0,0) ellipse (4 and 4);% a circle
\draw[fill=blue!7] (-4,0) arc (180:360:4 and 4);% left half of the circle starting at (-4,0) from 180 to 360
\draw[fill=white!7] (0,-3) ellipse (3 and 3);% a circle
\draw (0,0.2) node {$A$};
\draw (0,-3.6) node {$C$};
\draw (-3.5,-3.1) node {$D$};
\draw (3.5,-3.1) node {$B$};
\draw (1.5,-3.2) node {$a$};
% Create right angle
\coordinate (A) at (0,0);
\coordinate (E) at (1.6,-1.4);
\coordinate (C) at (0,-3);
\MarkRightAngle{A}{E}{C}
\draw[dashed] (0,-3) -- (1.6,-1.4);
\draw[-,thick] (0,0) -- (-3,-2.7) node[left, midway] {\footnotesize $b$};
\draw[-,thick] (0,0) -- (3,-2.7) node[right, midway] {\footnotesize $E$};
\draw[-,thick] (0,0) -- (0,-3) node[left, midway] {\footnotesize $a$};
\draw[-,thick] (-3,-2.7) -- (0,-3);
\draw[-,thick] (3,-2.7) -- (0,-3);
\end{tikzpicture}
\end{document}
```

The question is:

**If I plot it with Julia, two circles with certain radius and center, can I compute the certain area that is not intersected with other geometry object like the solution above?**