# amsmath

## https://michael-prokop.at/latextug/amsldoc.pdf

# Table of Contents

- Add line by line comments to math proofs
`\begin{equation}`

vs`\begin{equation*}`

- What does a double ampersand (
`&&`

) mean?

# Add line by line comments to math proofs howto

- Use
`\begin{algin*}`

along with`&&`

:

```
\begin{align*}
3+x &=4 && \text{we are trying to solve for } x\\
x &=4-3 && \text{Subtract 3 from both sides}\\
x &=1 && x \text{ must be one}
\end{align*}
```

\[\begin{align*}
3+x &=4 && \text{we are trying to solve for } x\\
x &=4-3 && \text{Subtract 3 from both sides}\\
x &=1 && x \text{ must be one}
\end{align*}
\]

`\begin{equation}`

vs `\begin{equation*}`

discussion

Each environment has both starred and unstarred forms,

where the unstarred forms have automatic numberingusing LATEX’s equation counter. You can suppress the number on any particular line by putting`\notag`

before the`\\`

# What does a double ampersand (`&&`

) mean? discussion

An align is a table-like structure, and `&`

is a column separator. The thing is that the columns in an align are `rlrlrlrlrl...`

, that is, **every other column is right aligned and left aligned.**

\[\begin{align}
a &= b\\
a &= b & text\\
a &= b && text
\end{align}
\]

- In
`a &= b`

,`a`

is right aligned while`=b`

is left aligned. - In
`a &= b & text`

,`text`

is right aligned. - In
`a &= b && text`

, an right-aligned empty column, followed by left aligned`text`

.