How can I enumerate an expression within $$ ... $$?

Question

Can someone help me, I want to enumerate my mathematical expressions that I wrote inside $$ ... $$.

$$y=f( \sum_{i=1}^{N} w_ix_i+w_0)$$

I used \align but it doesn't work, I even used \begin{equation}

Please help

Are you used to MathJax, where it's indeed permissible to insert line breaks inside a $$ ... $$ group? Are you using PlainTeX or LaTeX? — Mico, Jun 19 '17 at 01:56

score 6 · Accepted Answer · edited Jun 19 '17 at 01:13

6

Like this?

\documentclass{article}


\usepackage{amsmath}


\begin{document}

\begin{align}
y& =f\biggl( \sum_{i=1}^{N} w_ix_i+w_0\biggr), \\
U&=i
\end{align}
\end{document}

P.S.: avoid $$ ... $$; use \[ ... \] or \begin{equation} ... \end{equation} instead.

edited Jun 19 '17 at 01:13

Au101

10,278

answered Jun 19 '17 at 01:04

JPi

13,595

! Paragraph ended before \align was complete. that's what i got when i use your proposition – Hala Elomrani Jun 19 '17 at 03:33
2

@HalaElomrani Definitely not with the code from this answer (as is). I can confirm that it works. If you have another problem, please ask a new separate question. – Henri Menke Jun 19 '17 at 03:44
it's working because you added the seconde ligne but if you keep just the first one , exactly like what i'm asking , it will not , i don"t know why , i'm a beginner user of LaTex – Hala Elomrani Jun 19 '17 at 03:48
Also, make sure you don't have blank lines in math mode. – JPi Jun 19 '17 at 11:19

Henri Menke · Answer 2 · 2017-06-19T01:36:00.300

3

It's not clear what you are looking for. If you are actually looking for a Plain TeX solution (which the $$...$$ syntax suggests), use \eqalignno. The third column holds the number.

$$\eqalignno{
  y &= f\biggl( \sum_{i=1}^{N} w_ix_i+w_0 \biggr) & (1)
}$$
\bye

You could also use amstex.

\input amstex
\TagsOnRight
$$\align
  y &= f\biggl( \sum_{i=1}^{N} w_ix_i+w_0 \biggr) \tag{1}
\endalign$$
\bye

The output is similar.

edited Jun 19 '17 at 01:36

answered Jun 19 '17 at 01:29

Henri Menke

109,596

Thank you first, but i'm using LaTex So the both solutions doesn't work – Hala Elomrani Jun 19 '17 at 03:38
1

@HalaElomrani This wasn't clear from the question. – Henri Menke Jun 19 '17 at 03:43

How can I enumerate an expression within $$ ... $$?

2 Answers2