Put tikz picture right under math formula

Question

I have a formula under which I need te put a drawing explaining part of the formula, I have the following MWE:

\documentclass{beamer}
\usepackage{tikz}

\usetikzlibrary{chains,shapes.multipart}
\usetikzlibrary{shapes,calc}
\usepackage{amsmath}
\usepackage[utf8]{inputenc}
\usetikzlibrary{automata,arrows,shapes,snakes,automata,backgrounds,petri,positioning}
\usetikzlibrary{calc}
\begin{document}
\begin{frame}
$F(t+\Delta, 0) = \underset{\begin{tikzpicture}[scale = 0.7]
\draw[->, thick] (-0.1,0) -- (2,0);
\draw[->,thick] (0,-0.1) -- (0,2.3);
\draw[-, thick] (0.3,-0.1) -- (0.3,0.1) node[inner sep=1pt,at start, anchor=north] (A)  {$t$};
\draw[-, thick] (1.7,-0.1) -- (1.7,0.1) node[inner sep=1pt,at start, anchor=north] (A)  {$t+\Delta$};
\draw[-, very thick, color=red!100] (0.3,0) -- (1.7,0);
\end{tikzpicture}}{\underbrace{F(t,0) - \lambda \int_{v = 0}^{\Delta}\overline{C_d}(t+v,0)dv}} + \int_{v=0}^{\Delta} f(t+v, \Delta - v) du + o(\Delta)$,
\end{frame}
\end{document}

which produces the following result:

I would like this picture to be drawn under directly under the curly braces.

Answer 1

You can put the picture in a \text or other box.

\documentclass{beamer}
\usepackage{tikz}

\usetikzlibrary{chains,shapes.multipart}
\usetikzlibrary{shapes,calc}
\usepackage{amsmath}
\usepackage[utf8]{inputenc}
\usetikzlibrary{automata,arrows,shapes,snakes,automata,backgrounds,petri,positioning}
\usetikzlibrary{calc}
\begin{document}
\begin{frame}
$F(t+\Delta, 0) = \underbrace{F(t,0) - \lambda 
\int_{v = 0}^{\Delta}\overline{C_d}(t+v,0)dv}_{\text{\begin{tikzpicture}[scale = 0.7]
\draw[->, thick] (-0.1,0) -- (2,0);
\draw[->,thick] (0,-0.1) -- (0,2.3);
\draw[-, thick] (0.3,-0.1) -- (0.3,0.1) node[inner sep=1pt,at start, anchor=north] (A)  {$t$};
\draw[-, thick] (1.7,-0.1) -- (1.7,0.1) node[inner sep=1pt,at start, anchor=north] (A)  {$t+\Delta$};
\draw[-, very thick, color=red!100] (0.3,0) -- (1.7,0);
\end{tikzpicture}}} + 
\int_{v=0}^{\Delta} f(t+v, \Delta - v) du + o(\Delta)$,
\end{frame}
\end{document}

Answer 2

slightly different alternative to nice marmot answer. differences (used baseline option for tikzpicture, defined styles) are indicated by % <---:

\documentclass{beamer}
\usepackage{amsmath}
\usepackage[utf8]{inputenc}
\usepackage{tikz}

\begin{document}
\begin{frame}
\frametitle{Domain}
    \begin{multline*}
F(t+\Delta, 0) = \\
    \underbrace{F(t,0) - \lambda\int\limits_{v = 0}^{\Delta} \overline{C_d}(t+v,0)dv}_{% <---
    \begin{tikzpicture}[baseline,             % <---
        N/.style = {font=\footnotesize,below},% <---
        every path/.style = {thick, ->}       % <---  
                        ]
\draw (-0.1,0) -- (2.5,0);                                 % <---
\draw (0,-0.1) -- (0,1.5);                                 % <---
\draw[-] (0.5,0.1) -- + (0,-0.2) node[N] (A)  {$t$};       % <---
\draw[-] (2.0,0.1) -- + (0,-0.2) node[N] (A)  {$t+\Delta$};% <---
\path[draw=red,very thick,-] (0.5,0) -- + (1.5,0);
    \end{tikzpicture}} +
\int\limits_{v=0}^{\Delta} f(t+v, \Delta - v) du + o(\Delta)
    \end{multline*}
\end{frame}
\end{document}