Math & Science ⇒ Equation system not working as I want to

[MathiasHan]

Hi folks,

I am kinda new to LaTeX and trying to build a presentation with some math.

I want to write these two equations, but not quite sure how to do it:

As for equation number (1) I am wondering on how I allign the equations meanwhile I just keep equation 1 and not equation 1 and 2

My code is currently:

Code: Select all

\begin{eqnarray}
F_{t+1} &=& F_t+F_t*(R_{t+1}-1)(1-\tau_{PAL})+\theta Y_{t+1} \\
&=& \theta Y_{t+1}+F_t(\tau_{PAL}+R_{t+1}(1-\tau_{PAL})),
\end{eqnarray}

, but this results with equation 1 and 2 whereas it should only be 1.

For equation number 4 I am not sure which codes to use

Can anyone help me?

Best regards MathiasH

[Stefan Kottwitz]

Hi Mathias,

welcome to the forum!

Here is a way:

Code: Select all

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation}
  \begin{split}
    F_{t+1} &= F_t+F_t*(R_{t+1}-1)(1-\tau_{PAL})+\theta Y_{t+1} \\
            &=  \theta Y_{t+1}+F_t(\tau_{PAL}+R_{t+1}(1-\tau_{PAL})),
  \end{split}
\end{equation} 
\end{document}

Never use eqnarray (any more), since that is not optimal. Better use align or any other environment of the amsmath package.

Stefan

[Johannes_B]

What is shown in the figure as equation four can be done using the cases environment of package amsmath.

[MathiasHan]

Thank you!!!

However, now I am stuck on this line which is normal text. Anyone have any clue on how to write it?

"If we let $\mathbf{\mu}(t+1)$ be the vector of the expected returns in year t+1 and let $\sum_=$" clearly does not work.

[Stefan Kottwitz]

Stuck with which detail? What does not work? Making bold? Then use \boldsymbol{\mu}.

Stefan

[MathiasHan]

Thanks! That one works perfectly now. Any idea of how I do the sigma with 2 lines under?

Such a great help!

[Stefan Kottwitz]

I guess that's the easiest straightforward way:

Code: Select all

\documentclass{article}
\begin{document}
$\underline{\underline{\sum}} x$
\end{document}

Strefan