# Top four LaTeX mistakes

Here are four of the most common typesetting errors I see in books and articles created with LaTeX.

1) Quotes

Quotation marks in LaTeX files begin with two back ticks, , and end with two single quotes, ''.

The first “Yes” was written as

Yes.''

in LaTeX while the one with the backward opening quote was written as

"Yes."

2) Differentials

Differentials, most commonly the dx at the end of an integer, should have a little space separating them from other elements. The “dx” is a unit and so it needs a little space to keep from looking like the product of “d” and “x.” You can do this in LaTeX by inserting \, before and between differentials.

The first integral was written as

\int_0^1 f(x) \, dx

while the second forgot the , and was written as

\int_0^1 f(x)  dx

The need for a little extra space around differentials becomes more obvious in multiple integrals.

The first was written as

dx \, dy = r \, dr \, d\theta

while the second was written as

dx  dy = r  dr  d\theta

3) Multi-letter function names

The LaTeX commands for typesetting functions like sin, cos, log, max, etc. begin with a backslash. The command log keeps “log,” for example, from looking like the product of variables “l”, “o”, and “g.”

The first example above was written as

\log e^x = x

and the second as

log e^x = x

The double angle identity for sine is readable when properly typeset and a jumbled mess when the necessary backslashes are left out.

The first example was written

\sin 2u = 2 \sin u \cos u

and the second as

sin 2u = 2 sin u cos u

4) Failure to use math mode

LaTeX uses math mode to distinguish variables from ordinary letters. Variables are typeset in math italic, a special style that is not the same as ordinary italic prose.

The first sentence was written as

Given a matrix $A$ and vector $b$, solve $Ax = b$.

and the second as

Given a matrix A and vector b, solve Ax = b.

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## 57 thoughts on “Top four LaTeX mistakes”

1. Martin

Following your argumentation in 3) and applied to example 2), I would say the *fifth* most commonly made mistake in Latex is to write “dx” as a product of two variables “d” and “x”. However, the differential “d” is no variable. It should therefore read $\mathrm{\,d}x$ instead of $\,dx$.

2. julian hodgson

Do you mean

dx \, dy = r , dr \, d\theta

dx , dy = r , dr \, d\theta

Thanks
Julian

?

3. Thanks. I had an issue with my blog almost four years ago now that caused all my backslashes to disappear. I found most of the problems, but not all. Hopefully you found the last one!

4. As a followup to Martin’s comment on 08/12/16, the same is true when typesetting e in example 3. As this is not a variable, it should not be italicized.

The above example would be written as

\log \mathrm{e}^x = x

5. “dx \, dy = r \, dr \, d\theta”, instead of “dx \, dy = r , dr \, d\theta”.

6. Thanks, Paul. I had a technical problem years ago where a lot of backslashes went missing from my site. I thought I may have replaced all the missing backslashes by now, but you just found another one.