LaTex fractions question

[DaveE]

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.

 

[FactChecker]

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".

 

[fresh_42]

I'm not sure I understood the question. Where exactly is the problem?

 

[DaveE]

I'm not sure I understood the question. Where exactly is the problem?

I might not have either . 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.

 

[FactChecker]

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.

 

[DaveE]

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.

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

$\int_0^t \frac{sin(t-\tau)}{(t-\tau)} \, d\tau$ / $\begin{vmatrix} 1 & 2 & 3 & 4 \\ a & b & c & d \\ x & y & z & w \end{vmatrix}$

 

[fresh_42]

Do you mean something like that?

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

$$ \dfrac{ \displaystyle{\int_0^t \dfrac{sin(t-\tau)}{(t-\tau)} \, d\tau }}{
\det\left(\begin{matrix}
1 & 2 & 3 & 4 \\
a & b & c & d \\
x & y & z & w
\end{matrix}\right)}$$

 

[FactChecker]

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:
$\int_0^t \frac{sin(t-\tau)}{(t-\tau)} \, d\tau \Bigg / \begin{vmatrix} 1 & 2 & 3 & 4 \\ a & b & c & d \\ x & y & z & w \end{vmatrix}$

 

[fresh_42]

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

 

[DaveE]

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.

 

[DaveE]

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.

 

[DaveE]

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 $\frac{a}{b}$.