latex large division sign in a math formula

Question

Hi,

I have been looking for an answer for some time now, hope you could give me a quick tip.

I have an equation with many divisions inside. i.e:

$\frac{\frac{a_1}{a_2}} {\frac{b_1}{b_2}}$

To make it more readable, I decided to change the large fraction into "/" sign. i.e.

$\frac{a_1}{a_2} / \frac{b_1}{b_2}$

The problem is that the "/" sign remains small, and it is quite ugly.

How do I change the "/" sign to have a big font? How do I make it more readable?

Thanks.

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Although I found the answer to my original question myself (use \left \middle \right), I finally decided to use Frank's method (dfrac instead of frac) as it made it more readable than the / sign.

Thanks for your help. Anna

Answer 1

I found the answer I was looking for. The thing to use here is the construct of

\left \middle \right

For example, in this case, two possible solutions are:

$\left( {\frac{a_1}{a_2}} \middle/ {\frac{b_1}{b_2}} \right) $

Or, in case the brackets are not necessary:

$\left. {\frac{a_1}{a_2}} \middle/ {\frac{b_1}{b_2}} \right. $

Answer 2

Another option is to use \dfrac instead of \frac, which makes the whole fraction larger and hence more readable.

And no, I don't know if there is an option to get something in between \frac and \dfrac, sorry.

Answer 3

A possible soluttion that requires tweaking, but is very flexible is to use one of \big, \Big, \bigg,\Bigg in front of your division sign - these will make it progressively larger. For your formula, I think

  $\frac{a_1}{a_2} \Big/ \frac{b_1}{b_2}$

looks nicer than \middle\ which is automatically sized and IMHO is a bit too large.