This question already has an answer here:

I'm new using latex, someone can help mw with this equation, please How can I do this equation?

enter image description here

marked as duplicate by Au101, Stefan Pinnow, Andrew, Zarko, Werner equations Oct 28 '16 at 21:31

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • 6
    welcome to tex.sx. this question should be helpful: Math symbol question: Vertical bar for ''evaluated at …'' – barbara beeton Oct 28 '16 at 19:07
  • Exactly as @barbarabeeton says. The fraction (assuming that's giving you difficulties) is $\frac{\delta T_{i}}{\delta D}$ (obviously the vertical line and the Q should also be within that same pair of $ ... $) – Au101 Oct 28 '16 at 19:09
  • Thanks, the vertical bar was my problem. I didn't know the comand big. This is the code $\frac{\delta T_{i}}{\delta D} \big|_{q}$ – Christian Raine Oct 28 '16 at 19:22

Hello welcome to the community. There are a couple ways to do this, I think the easiest and most universal (if you plan on adjusting the sizing or environment of the math display) is the following:

\left. \frac{\delta T_i}{\delta D} \right|_Q

Latex Output

Not the answer you're looking for? Browse other questions tagged or ask your own question.