I get the `missing $ inserted error`

for the following code:

```
\begin{equation}
C = $ \frac{2}{\omega^2N^2\mu\pia} $
\end{equation}
```

I have tried out different changes based on Googling for this error, but nothing seems to help. Any suggestions would be appreciated.

## Best Answer

`$`

inside the`equation`

environment. You can't use math mode (ie,`$...$`

inside math mode (ie,`\begin{equation}... \end{equation}`

)`equation`

environment.`\pia`

should be`\pi a`

. Note the space.Code: