FatalMath Mode
Mismatched \left and \right Delimiters
! Extra \right.
What this error means
\left and \right must always appear as a matched pair in the same math group. A \right without a preceding \left, or a \left without a closing \right, causes this error.
Common causes
- A \right) or \right] with no matching \left
- \left and \right on different nesting levels due to missing braces
- Accidentally deleted the \left or \right from a pair
How to fix it
Ensure every \left delimiter has a matching \right delimiter in the same math group. Use \left. (with a period) as an invisible delimiter when you need an asymmetric pair.
Code examples
Causes the error
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[ f(x) = \right) x^2 \] % \right without \left
\end{document}Fixed
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[ f(x) = \left( x^2 \right) \]
\end{document}Related errors
Test the fix live
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