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.

**Related posts**:

- Microsoft equation editor
- Converting Excel tables to LaTeX
- Typesetting music in LaTeX
- Contrasting Word and LaTeX
- Things that work best when you don’t notice them

For daily tips on LaTeX and typography, follow @TeXtip on Twitter.

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 $\,dx$.