# Draw circles, half plane, angles

How can I draw

A circle with center z and radius R. A circle with center z and radius r, smaller than R. Label above and below the radius R, label just above radius r.

Three consecutive half-planes, one inside another, which are formed by 3 consecutive vertical lines. I want the color of the background of each strip, that the consecutive vertical lines create, to fade from the first to the last, but the vertical lines still be visible. Finally in each strip I need 3 labeled horizontal lines, crossing each strip.

• one sketch says more than 1000 words ... provide a (hand drawn) image, what you like to obtain. and also show us, what you try so far. Feb 19 '18 at 2:23
• Homework you want us to do for you?
– cfr
Feb 19 '18 at 2:48
• no it is for a presentation with beamer Feb 19 '18 at 11:59

I hope to have interpreted correctly what you want. UPDATE: I hope to addressed your requests. (The first one I did not understand, but you said you can do it yourself. ;-)

\documentclass[border=1mm,tikz]{standalone}
\begin{document}

\begin{tikzpicture}
\node[circle,draw,minimum width=5mm,fill=black,label=below:$z$]  (z) at (0,0) {};
\node[circle,draw,minimum width=3cm,draw,label=above:$R$,label=below:$R$] at (z){};
\node[circle,draw,minimum width=2cm,draw,label=below:$r$] at (z){};
\end{tikzpicture}

\begin{tikzpicture}
\foreach \Color/\Label [count=\X] in {red/label 1,green/label 2,blue/label 3}
{
\draw[thick](3*\X,-2) -- (3*\X,2);
\draw[left color=\Color] (3*\X,-2) rectangle ($(3*\X,2)+(3,0)$);
\draw[thick](3*\X,0)--++(3,0)node[above,midway]{\Label};
}
\end{tikzpicture}
\end{document}


• In the circles, I want to add the 2 radius and the labels be written just like the crossing lines of the half planes. But I think I can manage to do it by my own, based on what you have done so far! Feb 19 '18 at 11:29
• Also, can we make the center dot a little bit thicker? Feb 19 '18 at 11:30
• Also I need each label on the lines in the half plane to be different! Feb 19 '18 at 12:08