LaTex fractions question

  • #1
DaveE
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Is there a better way to get fractions to display like ## \rm{(a+b)/(c+d)}## instead of ## \frac{a+b}{c+d}##? Sometimes I'd like LaTex to do formatting "inside" the fraction; let's say with an integral symbol, for example.
 
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  • #2
DaveE said:
Is there a better way to get fractions to display like ## \rm{(a+b)/(c+d)}## instead of ## \frac{a+b}{c+d}##? Sometimes I'd like LaTex to do formatting "inside" the fraction; let's say with an integral symbol, for example.
For that, you do not need to use the LaTex frac. You can just type it in. I have never had a problem nesting LaTex formats, but I am not a "power user".
 
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  • #3
I'm not sure I understood the question. Where exactly is the problem?
 
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  • #4
fresh_42 said:
I'm not sure I understood the question. Where exactly is the problem?
I might not have either :wink: . I may need to experiment more.

I was thinking that maybe someone would just say try "\ifrac{}{}" instead. BTW, I know, I made that one up, there is no \ifrac (I think).

I guess the simplest version is how do I do this with a command as simply as \frac instead of turning off their formatting and doing it myself inside of \rm. I'm suspecting not since I'm not hearing a simple answer.
 
  • #5
Or the answer is so simple that we don't know what more to say. Just type it in. If you have an example of a problem with nested LaTex formats, maybe someone can help. You may need to backslash some special characters for LaTex to take them literally.
 
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  • #6
FactChecker said:
Or the answer is so simple that we don't know what more to say. Just type it in. If you have an example of a problem with nested LaTex formats, maybe someone can help. You may need to backslash some special characters for LaTex to take them literally.
Yes, I think you're right. This stuff isn't so bad. Unless you think it's supposed to make sense, LOL.

## \sum_{n=0}^\infty a_n x^n ## / ## \int_0^t H(t-\tau) \, d\tau ##

## \int_0^t \frac{sin(t-\tau)}{(t-\tau)} \, d\tau ## / ##
\begin{vmatrix}
1 & 2 & 3 & 4 \\
a & b & c & d \\
x & y & z & w
\end{vmatrix} ##
 
  • #7
Do you mean something like that?

$$
\dfrac{ \displaystyle{\sum_{n=0}^\infty a_n x^n }}{ \displaystyle{\int_0^t H(t-\tau) \, d\tau }}
$$

$$ \dfrac{ \displaystyle{\int_0^t \dfrac{sin(t-\tau)}{(t-\tau)} \, d\tau }}{
\det\left(\begin{matrix}
1 & 2 & 3 & 4 \\
a & b & c & d \\
x & y & z & w
\end{matrix}\right)}$$
 
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  • #8
DaveE said:
Yes, I think you're right. This stuff isn't so bad. Unless you think it's supposed to make sense, LOL.

## \sum_{n=0}^\infty a_n x^n ## / ## \int_0^t H(t-\tau) \, d\tau ##

## \int_0^t \frac{sin(t-\tau)}{(t-\tau)} \, d\tau ## / ##
\begin{vmatrix}
1 & 2 & 3 & 4 \\
a & b & c & d \\
x & y & z & w
\end{vmatrix} ##
Are you happy with that? It seems to be a natural consequence of what you asked for, although I would recommend that you at least enclose the numerator and denominator in parenthesis to make it clearer. But you would also have to do that if you wrote it by hand.
If you want the forward slash to be larger, you can use \big, \Big, \bigg, and \Bigg in LaTex to make progressively larger slashes. This is \Bigg:
## \int_0^t \frac{sin(t-\tau)}{(t-\tau)} \, d\tau \Bigg /

\begin{vmatrix}

1 & 2 & 3 & 4 \\

a & b & c & d \\

x & y & z & w

\end{vmatrix} ##
 
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  • #9
FactChecker said:
Are you happy with that? It seems to be a natural consequence of what you asked for, although I would recommend that you at least enclose the numerator and denominator in parenthesis to make it clearer. But you would also have to do that if you wrote it by hand.
If you want the forward slash to be larger, you can use \big, \Big, \bigg, and \Bigg in LaTex to make progressively larger slashes. This is \Bigg:
## \int_0^t \frac{sin(t-\tau)}{(t-\tau)} \, d\tau \Bigg /

\begin{vmatrix}

1 & 2 & 3 & 4 \\

a & b & c & d \\

x & y & z & w

\end{vmatrix} ##
Or even easier (and I think better to read) ...
$$
\begin{vmatrix}

1 & 2 & 3 & 4 \\

a & b & c & d \\

x & y & z & w

\end{vmatrix}^{-1} \displaystyle{\int_0^t \dfrac{sin(t-\tau)}{(t-\tau)} \, d\tau}
$$
... if not even define ##A^{-1}:=
\begin{pmatrix}
1 & 2 & 3 & 4 \\
a & b & c & d \\
x & y & z & w
\end{pmatrix}## and write ##
\displaystyle{\int_0^t |\det(A)|\dfrac{sin(t-\tau)}{(t-\tau)} \, d\tau}## which immediately refers to the transformation theorem: https://en.wikipedia.org/wiki/Integration_by_substitution#Substitution_for_multiple_variables
 
  • #10
fresh_42 said:
Do you mean something like that?

$$
\dfrac{ \displaystyle{\sum_{n=0}^\infty a_n x^n }}{ \displaystyle{\int_0^t H(t-\tau) \, d\tau }}
$$

$$ \dfrac{ \displaystyle{\int_0^t \dfrac{sin(t-\tau)}{(t-\tau)} \, d\tau }}{
\det\left(\begin{matrix}
1 & 2 & 3 & 4 \\
a & b & c & d \\
x & y & z & w
\end{matrix}\right)}$$
Nope. That's the normal (i.e. good) way to format these, LOL.
 
  • #11
FactChecker said:
Are you happy with that? It seems to be a natural consequence of what you asked for, although I would recommend that you at least enclose the numerator and denominator in parenthesis to make it clearer. But you would also have to do that if you wrote it by hand.
If you want the forward slash to be larger, you can use \big, \Big, \bigg, and \Bigg in LaTex to make progressively larger slashes. This is \Bigg:
## \int_0^t \frac{sin(t-\tau)}{(t-\tau)} \, d\tau \Bigg /

\begin{vmatrix}

1 & 2 & 3 & 4 \\

a & b & c & d \\

x & y & z & w

\end{vmatrix} ##
I think this is as good as it can get. I didn't really know about \big, thanks.
 
Last edited:
  • #12
fresh_42 said:
Or even easier (and I think better to read) ...
$$
\begin{vmatrix}

1 & 2 & 3 & 4 \\

a & b & c & d \\

x & y & z & w

\end{vmatrix}^{-1} \displaystyle{\int_0^t \dfrac{sin(t-\tau)}{(t-\tau)} \, d\tau}
$$
... if not even define ##A^{-1}:=
\begin{pmatrix}
1 & 2 & 3 & 4 \\
a & b & c & d \\
x & y & z & w
\end{pmatrix}## and write ##
\displaystyle{\int_0^t |\det(A)|\dfrac{sin(t-\tau)}{(t-\tau)} \, d\tau}## which immediately refers to the transformation theorem: https://en.wikipedia.org/wiki/Integration_by_substitution#Substitution_for_multiple_variables
Yes, these are better. The example was arbitrary and stupid just to show a more complex problem than ##\frac{a}{b}##.
 
  • #13
DaveE said:
I think this is as good as it can get. I didn't really know about \big, thanks.
You are not alone. When I am doing anything slightly complicated in LaTex I end up Googling it. Even if I know a trick today, next week I will have to Google it again. :-) I had to Google this to answer your question.
 
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  • #14
FactChecker said:
You are not alone. When I am doing anything slightly complicated in LaTex I end up Googling it. Even if I know a trick today, next week I will have to Google it again. :-) I had to Google this to answer your question.
I have loaded my keyboard with 67 shortcuts. As a result, I use these all the time rather than learning new ones. And if, as your useful big-enlargements, I'll probably forget them again.
 

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