2

Here are a group of mathematical expressions:

$$arg\ \underset{\theta}{max} \underset{n}{\prod}P(Y_n|\theta)$$
$$=arg\ \underset{\theta}{max} \underset{n}{\prod}\theta^{Y_n}(1-\theta)^{1-Y_n}$$
$$=arg\ \underset{\theta}{max} \sum log\theta^{Y_n}(1-\theta)^{1-Y_n}$$
$$=arg\ \underset{\theta}{max} \sum[Y_n log\theta + (1-Y_n)log(1-\theta)] $$
Optimizing problem:
$$=-arg\ \underset{\theta}{min} \sum[Y_n log\theta + (1-Y_n)log(1-\theta)] $$

I am trying to align them to the left. I tried putting them inside %\begin{align*} ... % \end{align*} without $$ signs. But no luck.

2
  • @Troy I've tried it but it does not serve my purpose.
    – Dipto_Das
    Jun 3, 2017 at 17:54
  • 2
    Please describe your problem better, which code (MWE) did you tried, and what is still the problem, for example mark it in the screenshot added to your question ...
    – Mensch
    Jun 3, 2017 at 18:08

2 Answers 2

1

Without a complete MWE, it's difficult to know what you're after, but I assume it's something like this:

enter image description here

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{align*}
    \arg\ \underset{\theta}{\max} \underset{n}{\prod}P(Y_n|\theta) & =\arg\ \underset{\theta}{\max} \underset{n}{\prod}\theta^{Y_n}(1-\theta)^{1-Y_n} \\
                                                                   & =\arg\ \underset{\theta}{\max} \sum \log\theta^{Y_n}(1-\theta)^{1-Y_n}           \\
                                                                   & =\arg\ \underset{\theta}{\max} \sum[Y_n \log\theta + (1-Y_n)\log(1-\theta)]      \\
    \intertext{Optimizing problem:}
                                                                   & =-\arg\ \underset{\theta}{\min} \sum[Y_n \log\theta + (1-Y_n)\log(1-\theta)]     \\
\end{align*}
alternatively:
\begin{flalign*}
    & \arg\ \underset{\theta}{\max} \underset{n}{\prod}P(Y_n|\theta) \\
    & =\arg\ \underset{\theta}{\max} \underset{n}{\prod}\theta^{Y_n}(1-\theta)^{1-Y_n} \\
    & =\arg\ \underset{\theta}{\max} \sum \log\theta^{Y_n}(1-\theta)^{1-Y_n}          \\
    & =\arg\ \underset{\theta}{\max} \sum[Y_n \log\theta + (1-Y_n)\log(1-\theta)]     \\
    \intertext{Optimizing problem:}
    & =-\arg\ \underset{\theta}{\min} \sum[Y_n \log\theta + (1-Y_n)\log(1-\theta)]    \\
\end{flalign*}
\end{document}

alternatively, perhaps you'd like flalign:

enter image description here

3
  • I do not want the first line to contain a = sign.
    – Dipto_Das
    Jun 3, 2017 at 17:41
  • @Dipto_Das if you provide a screenshot of your desired output, it'd be most helpful
    – cmhughes
    Jun 3, 2017 at 18:05
  • @Dipto_Das see my update
    – cmhughes
    Jun 4, 2017 at 8:31
1

The following may be what you're looking for. Note the use of \arg, \max, \min, and \log to generate upright math-operator expressions. I've also replaced the two instances of \underset{n}{\prod} with \prod_n.

enter image description here

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{align*}
& \arg\max_\theta \prod_n P(Y_n\mid\theta)\\
&=\arg\max_\theta \prod_n \theta^{Y_n}(1-\theta)^{1-Y_n}\\
&=\arg\max_\theta \sum \log\bigl(\theta^{Y_n}(1-\theta)^{1-Y_n}\bigr)\\
&=\arg\max_\theta \sum [Y_n \log\theta + (1-Y_n)\log(1-\theta)]\\
\intertext{Optimizing problem:}
&-\arg\min_\theta \sum[Y_n \log\theta + (1-Y_n)\log(1-\theta)] 
\end{align*}
\end{document}
2
  • Your code does what I want, but it places everything in the center of the page. I want them all to start from the left margin. How can I do that?
    – Dipto_Das
    Jun 3, 2017 at 18:44
  • @Dipto_Das - You could (a) switch from an align* environment to an flalign* environment and (b) add a & marker at the end of one of the math lines (but before the double line-break directive). E.g., change \prod_n P(Y_n\mid\theta) to \prod_n P(Y_n\mid\theta)&.
    – Mico
    Jun 3, 2017 at 19:07

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