[Tex/LaTex] Big equation does not fit in beamer

beamerequations

I have copied a math expression from Mathematica in a beamer frame.

The equation is so long that although I have splitted it into several lines, which are separated by a plus symbol, still does not fit in the frame.

I have tried all that I have found here, I have put the equation in a minipage, and then resized it to the text width, even I have enlargered the frame with \geometry but neither of this works for me.

The \geometry will change all my others frames and I don't want that.

Besides I want that the equation be aligned to the left side of the frame and I don't know how.

This is my code:

\documentclass{beamer}
\begin{document}
\begin{frame}

the scattering amplitude

\resizebox{\textwidth}{!}{
\begin{minipage}[]{\textwidth}
\large{
\begin{eqnarray}
 \frac{2 \left(\text{tr} \left(\text{e}^4 \left(m_e-\bar{\gamma }\cdot \bar{K}\right).\left(\bar{\gamma }\cdot \bar{\varepsilon }\left(\text{k}_2\right)\right).\left(\bar{\gamma }\cdot \left(-\overline{\text{k}_2}-\bar{K}\right)+m_e\right).\left(\bar{\gamma }\cdot \bar{\varepsilon }^*\left(\text{q}_2\right)\right).\left(\bar{\gamma }\cdot \left(-\overline{\text{k}_2}-\bar{K}+\overline{\text{q}_2}\right)+m_e\right).\left(\bar{\gamma }\cdot \bar{\varepsilon }^*\left(\text{q}_1\right)\right).\left(\bar{\gamma }\cdot \left(-\overline{\text{k}_2}-\bar{K}+\overline{\text{q}_1}+\overline{\text{q}_2}\right)+m_e\right).\left(\bar{\gamma }\cdot \bar{\varepsilon }\left(\text{k}_1\right)\right)\right)\right)}
   {\left(\bar{K}^2-m_e^2\right).\left(\left(\overline{\text{k}_2}+\bar{K}\right){}^2-m_e^2\right).\left(\left(\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_2}\right){}^2-m_e^2\right).\left(\left(\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}-\overline{\text{q}_2}\right){}^2-m_e^2\right)}
+\frac{2 \left(\text{tr} \left(\text{e}^4 \left(\bar{\gamma }\cdot \left(\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}-\overline{\text{q}_2}\right)+m_e\right).\left(\bar{\gamma }\cdot \bar{\varepsilon }^*\left(\text{q}_2\right)\right).\left(\bar{\gamma }\cdot \left(\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}\right)+m_e\right).\left(\bar{\gamma }\cdot \bar{\varepsilon }\left(\text{k}_2\right)\right).\left(\bar{\gamma }\cdot \left(\bar{K}-\overline{\text{q}_1}\right)+m_e\right).\left(\bar{\gamma }\cdot \bar{\varepsilon }^*\left(\text{q}_1\right)\right).\left(\bar{\gamma }\cdot \bar{K}+m_e\right).\left(\bar{\gamma }\cdot \bar{\varepsilon }\left(\text{k}_1\right)\right)\right)\right)}
   {\left(\bar{K}^2-m_e^2\right).\left(\left(\bar{K}-\overline{\text{q}_1}\right){}^2-m_e^2\right).\left(\left(\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}\right){}^2-m_e^2\right).\left(\left(\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}-\overline{\text{q}_2}\right){}^2-m_e^2\right)}
+\frac{2 \left(\text{tr} \left(\text{e}^4 \left(\bar{\gamma }\cdot \left(\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}-\overline{\text{q}_2}\right)+m_e\right).\left(\bar{\gamma }\cdot \bar{\varepsilon }^*\left(\text{q}_2\right)\right).\left(\bar{\gamma }\cdot \left(\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}\right)+m_e\right).\left(\bar{\gamma }\cdot \bar{\varepsilon }^*\left(\text{q}_1\right)\right).\left(\bar{\gamma }\cdot \left(\overline{\text{k}_2}+\bar{K}\right)+m_e\right).\left(\bar{\gamma }\cdot \bar{\varepsilon }\left(\text{k}_2\right)\right).\left(\bar{\gamma }\cdot \bar{K}+m_e\right).\left(\bar{\gamma }\cdot \bar{\varepsilon }\left(\text{k}_1\right)\right)\right)\right)}
   {\left(\bar{K}^2-m_e^2\right).\left(\left(\overline{\text{k}_2}+\bar{K}\right){}^2-m_e^2\right).\left(\left(\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}\right){}^2-m_e^2\right).\left(\left(\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}-\overline{\text{q}_2}\right){}^2-m_e^2\right)}
\end{eqnarray}
}
\end{minipage}
}

\end{frame}
\end{document}

In here, as you can see, I have made not any splitting or enlarging of the page.

So maybe you can start to teach me how to split the expression properly.

Best Answer

If you're going to show this monster of a math expression at all, you should give your audience a fighting chance to take in at least some of the details. There are 3 additive components to the full equation, each consisting of fractions with dreadfully long numerators and denominators. I suggest you break up each of the numerators across 3 lines, and each of the denominators across 2 lines.

Note that I've removed all 78 \left directives, all 78 \right directives, all 24 \cdot directives, and lots of other . (dot) terms. They simply do not belong in a well-typeset math expression. I could have also eliminated further groups of parentheses that appear to be there purely for the convenience of Mathematica, but I chose to give it a rest. I did add, though, large parentheses to enclose the multi-line numerator and denominator terms.

enter image description here

\documentclass{beamer}
\usepackage{amsmath}
\DeclareMathOperator{\tr}{tr} % trace operator?
\begin{document}
\begin{frame}
\footnotesize  % <--- yes, this is needed
\begin{align*}
&\frac{\left(\begin{aligned}
2 \tr \bigl[&\text{e}^4 (m_e-\bar{\gamma} \bar{K})(\bar{\gamma} \bar{\varepsilon}(\text{k}_2))(\bar{\gamma} (-\overline{\text{k}_2}-\bar{K})+m_e)(\bar{\gamma} \bar{\varepsilon}^*(\text{q}_2))\\
&\times(\bar{\gamma} (-\overline{\text{k}_2}-\bar{K}+\overline{\text{q}_2})+m_e)(\bar{\gamma} \bar{\varepsilon}^*(\text{q}_1))\\
&\times(\bar{\gamma} (-\overline{\text{k}_2}-\bar{K}+\overline{\text{q}_1}+\overline{\text{q}_2})+m_e)(\bar{\gamma} \bar{\varepsilon}(\text{k}_1))\bigr]
\end{aligned}\right)}%
{\left(\begin{aligned}
&(\bar{K}^2-m_e^2)((\overline{\text{k}_2}+\bar{K})^2-m_e^2)\\
&\times((\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_2})^2-m_e^2)((\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}-\overline{\text{q}_2})^2-m_e^2)
\end{aligned}\right)}\\[1ex]
{}+{}
&\frac{\left(\begin{aligned}
2 \tr \bigl[&\text{e}^4 (\bar{\gamma} (\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}-\overline{\text{q}_2})+m_e)(\bar{\gamma} \bar{\varepsilon}^*(\text{q}_2))\\
&\times(\bar{\gamma} (\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1})+m_e)(\bar{\gamma} \bar{\varepsilon}(\text{k}_2))(\bar{\gamma} (\bar{K}-\overline{\text{q}_1})+m_e)\\
&\times(\bar{\gamma} \bar{\varepsilon}^*(\text{q}_1))(\bar{\gamma} \bar{K}+m_e)(\bar{\gamma} \bar{\varepsilon}(\text{k}_1))\bigr]
\end{aligned}\right)}%
{\left(\begin{aligned}
&(\bar{K}^2-m_e^2)((\bar{K}-\overline{\text{q}_1})^2-m_e^2)\\
&\times((\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1})^2-m_e^2)((\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}-\overline{\text{q}_2})^2-m_e^2)
\end{aligned}\right)}\\[1ex]
{}+{}&
\frac{\left(\begin{aligned}
2 \tr \bigl[&\text{e}^4 (\bar{\gamma} (\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}-\overline{\text{q}_2})+m_e)(\bar{\gamma} \bar{\varepsilon}^*(\text{q}_2))\\
&\times(\bar{\gamma} (\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1})+m_e)(\bar{\gamma} \bar{\varepsilon}^*(\text{q}_1))\\
&\times(\bar{\gamma} (\overline{\text{k}_2}+\bar{K})+m_e)(\bar{\gamma} \bar{\varepsilon}(\text{k}_2))(\bar{\gamma} \bar{K}+m_e)(\bar{\gamma} \bar{\varepsilon}(\text{k}_1))\bigr]
\end{aligned}\right)}%
{\left(\begin{aligned}
&(\bar{K}^2-m_e^2)((\overline{\text{k}_2}+\bar{K})^2-m_e^2)\\
&\times((\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1})^2-m_e^2)((\overline{\text{k}_2}+\bar{K}-\overline{\text{q}_1}-\overline{\text{q}_2})^2-m_e^2)
\end{aligned}\right)}
\end{align*}
\end{frame}
\end{document}
Related Question