# Write this equation

I want to write this equation in this way down but I have been unsuccessful. How can I improve this codes in order to get the equation below?

$DeltaC{t} = \left\{ \begin{array}{ll} -1.40- 0.588w_{t-1} - 0.5351\DeltaC_{t-1}+ 0.169\DeltaBC_{t-1} & \mbox{ if w_{t-1}<- 0.62} \\ -1.40 - 0.588w_{t-1} - 0.5351\DeltaC_{t-1} + 0.169\DeltaBC_{t-1} & \mbox{w_{t-1}>0.62} \end{array} \right.$


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What exactly is this for? (Also, you only have one column for the array; remove an l.) – Sean Allred Jan 13 '14 at 0:56
It is a regression. My goal is to write the equation in the same form that the second one below without number in parenthesis. I want to write the equation without those in parentesis. Please just consider the first one and tell me how it is working!. – ntamjo achille Jan 13 '14 at 1:09
Unfortunately, you haven't provided a definition for \DeltaC or \DeltaBC in your post; please expand it into a minimal working example (MWE) so someone can tell you what's actually going wrong. – Sean Allred Jan 13 '14 at 1:11

I think you want cases from amsmath. Also, instead of \mbox, it is better to use \text.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
$DeltaC{t} = \begin{cases} -1.40- 0.588w_{t-1} - 0.5351\Delta_{t-1}+ 0.169\Delta_{t-1} & \text{if w_{t-1}<- 0.62} \\ -1.40 - 0.588w_{t-1} - 0.5351\Delta_{t-1} + 0.169\Delta_{t-1} & \text{w_{t-1}>0.62} \end{cases}$
\end{document}


Since your equation is too long, I have split it in to two lines and added some space adjustments and fine tuning by Enrico. (Thanks to egreg).

\documentclass{article}
\usepackage{amsmath}

\newcommand{\DeltaC}[1]{%
\Delta\pi^{\textnormal{Services}}_{#1}%
}
\newcommand{\DeltaBC}[1]{%
\Delta\pi^{\textnormal{Goods}}_{#1}%
}

\begin{document}

$\DeltaC{t} = \begin{cases} -0.03_{(0.08)} - 0.08_{(0.05)} + 0.09_{(0.18)} \DeltaC{t-1} \\ \qquad{} + 0.12_{(0.03)}\DeltaBC{t-1} + u_{2t}, & \text{if w_{t-1}<-0.62,} \\[2ex] 0.38_{(0.15)} - 0.12_{(0.04)} + 0.40_{(0.07)} \DeltaC{t-1} \\ \qquad{} + 0.18_{(0.06)}\DeltaBC{t-1} + u_{2t}, & \text{if  w_{t-1} > 2.2,} \end{cases}$
\end{document}


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your response was very helpful,particularly the first option(with cases), to write this equation. Thanks – ntamjo achille Jan 16 '14 at 14:26
@ntamjoachille Glad that was useful. You can also accept answers and upvote them if they are useful :) – Harish Kumar Jan 16 '14 at 14:58
where can i upvote? – ntamjo achille Jan 16 '14 at 15:01

Your equation actually only has one column (but it has two rows). But in this case, it would be better to use the cases environment from amsmath.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
$\Delta\pi_t^\text{Services} = \begin{cases} -0.03_{0.08} - 0.08_{0.05} + 0.09_{0.18} \Delta\pi_{t-1}^\text{Services} + 0.12_{0.03} \Delta\pi_{t-1}^\text{Goods} + u_{2t} & w_{t-1} \leq 2.2 \\ 0.38_{0.15} - 0.12_{0.04} + 0.40_{0.07} \Delta\pi_{t-1}^\text{Services} + 0.18_{0.06} \Delta\pi_{t-1}^\text{Goods} + u_{2t} & w_{t-1} > 2.2 \end{cases}$
\end{document}

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@Harish [ DeltaCanada_{t} = \begin{cases} -1.40(0.02) - 0.58(1.5e-8)w_{t-1} - 0.53(0.14)\DeltaCanada_{t-1}+ 0.169(0.03)\DeltaBritishColumbia_{t-1} & \text{ if $w_{t-1} \leq 0.62$} \\ -0.73(0.76) - 0.15(0.17)w_{t-1} - 0.99(2.5e-7)\DeltaCanada_{t-1} + 0.24(0.13) \DeltaBritishColumbia_{t-1} & \text{$w_{t-1}>0.62$} \end{cases} \ ] – ntamjo achille Jan 13 '14 at 16:41
@ntamjoachille What? – Sean Allred Jan 13 '14 at 17:10
I have tried to write it in a clearer way. You can see it in this link:tex.stackexchange.com/questions/153871/… – ntamjo achille Jan 13 '14 at 17:13
@ntamjoachille It is certainly not clear to anyone who doesn't know the topic of your work. Please do not post duplicate questions like this; if the answers here don't actually answer your original question, say so here — not in a new post. – Sean Allred Jan 13 '14 at 18:53
i have combined all your suggestions on my latex codes and now it is working. – ntamjo achille Jan 15 '14 at 0:05