Variable names with spaces in equations

Question

I want to write a fomula

\begin{equation}
    fractional bandwidth = \frac{f_U-f_L}{f_C} \geq 0.25
\end{equation}

but it can't have any space between "fractional" and "bandwidth" How can I do that? Thank you!

Answer 1

Use \text of package amsmath to format text in math equations.

\usepackage{amsmath}
...

\begin{equation}
    \text{fractional bandwidth} = \frac{f_U-f_L}{f_C} \geq 0.25
\end{equation}

However, if these words were intended to be formatted like they are but with a space in between, you can insert spaces in math mode like this (a full list of spacing commands can be found here).

\begin{equation}
    fractional \: bandwidth  = \frac{f_U-f_L}{f_C} \geq 0.25
\end{equation}