Here's something that turned up from time to time.

I type:

. . $\displaystyle \text{[m{a}th]}\theta\text{[/m{a}th]} $ is in a right triangle.

. . And: $\displaystyle \text{[m{a}th]}\backslash \text{tan} \backslash\text{theta} = \backslash \text{frac}\{\text{opp}\}\{\text{adj}\}\text{[/m{a}th]} $

And this is what is produced:

. . $\displaystyle \theta$ is in a right triangle.

. . And: $\displaystyle \tan\theta = \frac{opp}{adj}$

Note that the first $\displaystyle \theta$ is smaller than the second one, $\displaystyle \theta.$

. . Yes, it's a trivial difference, I agree.

Quite by accident, I found a correction for it.

Precede the first $\displaystyle \theta$ with a.space

. . Type: .$\displaystyle \text{[m{a}th]}\;\theta\text{[/m{a}th]} $ is in a right triangle.

. . and we get: .$\displaystyle \theta$ is in a right triangle.

Always glad to be of service . . .