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Latex question, new line

by Redbelly98
Tags: latex, line
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Redbelly98
#1
Oct31-08, 11:54 PM
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I can't seem to generate multiple lines within a single [ tex ][ /tex ] block. It's supposed to happen if I type \\ but it just never works for me.

Example:

[tex]
f_1(x) = x \\
f_2(x) = 1-x^2
[/tex]

The "f2(x)" is supposed to start on a new line.

What am I doing wrong?
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phyzmatix
#2
Nov1-08, 12:05 AM
P: 362
Quote Quote by Redbelly98 View Post
I can't seem to generate multiple lines within a single [ tex ][ /tex ] block. It's supposed to happen if I type \\ but it just never works for me.

Example:

[tex]
f_1(x) = x \\
f_2(x) = 1-x^2
[/tex]

The "f2(x)" is supposed to start on a new line.

What am I doing wrong?
Unfortunately I'm not going to be of any help to you. I've also tried this numerous times, but to the same effect.
Hootenanny
#3
Nov1-08, 05:25 AM
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I don't think that the \\ has ever worked on the forums, it must be some kind of bug in the software. However, one can start new lines using the flalign environment.

[tex]
\begin{flalign*}
f_1\left(x\right) & = & & x\\
f_2\left(x\right) & = & & 1-x^2\\
f_3\left(x\right) & = & & \frac{f_1}{f_2} \\
& = & & \frac{x}{1-x^2}
\end{flalign*}
[/tex]

And the code:
\begin{flalign*}
f_1\left(x\right) & = & & x\\
f_2\left(x\right) & = & & 1-x^2\\
f_3\left(x\right) & = & & \frac{f_1}{f_2} \\
& = & & \frac{x}{1-x^2}
\end{flalign*}
The * is used to suppress line enumeration. The alignment of each element is fixed to alternate between left and right as shown below

\begin{flalign*}
right & left & right & ... \\
right & left & right & ... \\
right & left & right & ... \\
\end{flalign*}
But you can add additional & separators to obtain the desired layout, as I have done above:

\begin{flalign*}
right & left &  & left \\
right & left &  & left \\
right & left &  & left \\
\end{flalign*}
I agree that this method is far more verbose than simply using \\ is mathmode, but it is the only work-a-round that i know of for PF. Note that the eqnarray environment does not display correctly either at PF.

Redbelly98
#4
Nov1-08, 08:50 AM
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Latex question, new line

Thanks Hoot. So the &'s help line up the equal signs. And if I just wanted to left-justify each line, each line would start with a &.

      \begin{flalign*}
      & f_1(x) = x \\ 
      & f_2(x) = 1-x^2
      \end{flalign*}
I also found this previous discussion in a locked thread:
http://www.physicsforums.com/showthr...x+line&page=19

However, in chroot's examples the code uses TWO begin and TWO end statements, eg.
\begin{equation*}
\begin{split}

So the single begin statement
\begin{flalign*}
is an improvement over that.

Thanks again!

RB
Hurkyl
#5
Nov1-08, 08:52 AM
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Quote Quote by Hootenanny View Post
II don't think that the \\ has ever worked on the forums
I've never known it to work in LaTeX either. (Remember that [ itex ] ... [/itex] is analogous to $ ... $, and [ tex ] ... [/tex] is analogous to \[ ... \])
Hootenanny
#6
Nov1-08, 09:00 AM
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Quote Quote by Hurkyl View Post
I've never known it to work in LaTeX either. (Remember that [ itex ] ... [/itex] is analogous to $ ... $, and [ tex ] ... [/tex] is analogous to \[ ... \])
Hmm, you're quite right: \\ only works in array enviroments in LaTeX
robphy
#7
Nov1-08, 10:20 AM
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[tex]
\]
This is the first line.\\
This is the second line.\\
This is the third line.
\[
E=mc^2
\]
This is another line.
\[
[/tex]

Click on the rendered image to see what I did.
Maybe some [tex]\LaTeX[/tex] expert can explain what is going on.
I suspect that the forum software already places us in a [tex]\LaTeX[/tex] environment... and these \[ \] break us out of it somehow.
cristo
#8
Nov1-08, 04:54 PM
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Quote Quote by robphy View Post
I suspect that the forum software already places us in a [tex]\LaTeX[/tex] environment... and these \[ \] break us out of it somehow.
Sounds precisely right to me: the [tex] tag acts like \[ and by typing \], you close the latex environment.
Redbelly98
#9
May30-11, 11:11 AM
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Now that we are using MathJax, I am revisiting how to generate multiple lines within a single LaTeX code block.

EDIT: Nevermind, I found out how to do this: http://www.physicsforums.com/showthread.php?p=261329

Also, scroll down post #1 here for multi-line examples: http://www.physicsforums.com/showthread.php?t=8997

Please disregard the following...


I just now noticed a problem with these old posts (for example Post #'s 1 and 3 above). Right now I see the LaTeX code, without the [_tex_] tags, enclosed in a box and left-right centered in the page. I have FireFox 4 and Windows 7.

Apparently MathJax doesn't like the double-backslash newline indicator, and that is preventing the code from being processed properly.

Testing:

Using same code from Post #1 again:
[tex]
f_1(x) = x \\
f_2(x) = 1-x^2
[/tex]

Same code, with double-backslash removed:
[tex]
f_1(x) = x
f_2(x) = 1-x^2
[/tex]

So the question is, is it possible anymore to generate a new line within the same [_tex_] code block? Hootenanny's trick in Post #3 used to work -- not that I am advocating going back to the old LaTeX system.
Hurkyl
#10
May30-11, 11:23 AM
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Here:
[tex]
\begin{align}
a & b \\
c & d
\end{align}
[/tex]

This one gives weird results:
[tex]
\begin{multline}
a b \\
c d
\end{multline}
[/tex]


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