diff --git a/main/math.tex b/main/math.tex
index acff4cd..8417baf 100644
--- a/main/math.tex
+++ b/main/math.tex
@@ -40,5 +40,5 @@
 \newcommand{\liminfni}{\liminf_{n \rightarrow \infty}}
 \newcommand{\limsupni}{\limsup_{n \rightarrow \infty}}
 \DeclareMathOperator\arctanh{arctanh}
-\DeclareMathOperator\arcosh{arcosh}
+\DeclareMathOperator\arccosh{arccosh}
 \DeclareMathOperator\arcsinh{arcsinh}