% !TeX TXS-program:compile = txs:///pdflatex

\documentclass[margin=5mm]{standalone}
\usepackage{tikz,xintexpr}

\begin{document}

\begin{tikzpicture}[line join=bevel,x=2cm,y=2cm,transform shape]
	\def\xoffset{0.35}
	\path[thick,->,>=latex] (0,-0.15)--(0,1.5) ;
	\filldraw[very thin,fill=brown!70!black] (-1,0) -- plot[samples=500,domain=-1:1] (\x,{\xintfloateval{(1-(\x)^2)*exp(\x)}}) -- (1,0) -- cycle ;
	\filldraw[very thin,fill=brown!85!black] (0.35,{(1-(0.35)*(0.35))*exp(0.35)}) --++ (0.6,0.2) -- plot[samples=500,domain=0.95:1.6] (\x,{(1-(\x-0.6)*(\x-0.6))*exp(\x-0.6)+0.2}) -- plot[draw=none,samples=500,domain=1:0.35] (\x,{(1-(\x)*(\x))*exp(\x)}) -- cycle ;
	\draw[thick,<->,>=latex] ([shift={(-73.3:0.1)}]1,0)--++(0.6,0.2) node[midway,sloped,below,font=\small] {3~cm} ;
\end{tikzpicture}

\end{document}