# writing equation: error ! Display math should end with 

I have a problem with writing this equation that displays the error in the object. I think I didn't understand well the syntax of writing equation.

$\DeltaV\textsubscript{pgm} \frac{q\DeltaV\textsubscript{T}}{C\textsubscript{pp}}$

• You used \$ inside of the maths environment started with $. Drop all those s in your equation, they are causing the problems. – Skillmon Sep 22 '18 at 18:03 ## 1 Answer As noted in my comment, you shouldn't use  inside of a displayed maths environment.  starts and ends inline maths. Also you shouldn't use \textsubscript inside of math mode as this is for text mode (as the name suggests). Subscript can be added with _ in math mode. For indices which should be printed upright because they are abbreviations or full words, you should use \text provided by amsmath. Your whole equation then becomes: \documentclass[preview]{standalone} \usepackage{amsmath} \begin{document} \[ \Delta V_{\mathrm{pgm}} \frac{q\Delta V_T}{C_{\mathrm{pp}}}$
\end{document}


EDIT: As noted by @egreg in the comments, the usage of \text depends on the context. If pgm and pp are textual objects then \text is correct in the above. If they are not textual then one should use \mathrm instead.

• \mathrm{pgm} maybe? – egreg Sep 22 '18 at 18:08
• @egreg depends on context that I don't know. If it's something textual then \text else \mathrm. – Skillmon Sep 22 '18 at 18:16
• @Skillmon true but in 99.99% of the time a superscript should be mathrm – David Carlisle Sep 22 '18 at 18:57