# Drawing a funnel with Tikz

Does anyone have a method for drawing a funnel in Tikz?

I am attempting to replicate the funnel drawn for this past year's AP Calculus BC free-response questions.

I have attached the image that I would like to recreate using Tikz below.

Any help would be much appreciated!

• Well, what do you have so far and where are you getting stuck? Since you are using a particular drawing package, presumably you have at least a passing familiarity with it. If not, there are plenty of examples to get you started (in the manual, here, on other sites ...). Or you can just use \includegraphics... and not worry about it. – cfr Jun 29 '16 at 3:18

Here is a starting point. You should be able to adjust this easily by reading the TikZ manual.

\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\foreach \sgn in {-,+}
\draw plot[domain=0:10] ({\sgn 1/20*(3+\x*\x)},\x);
\foreach \h in {0,5,10}
\draw (0,0) -- node[right] {$h$} (0,5);
\draw (0,5) -- node[above] {$r$} ({-1/20*(3+5*5)},5);