diff --git a/contents/trigonometry.tex b/contents/trigonometry.tex
index 237b125..f7989f9 100644
--- a/contents/trigonometry.tex
+++ b/contents/trigonometry.tex
@@ -23,7 +23,7 @@ $\cos\frac{\pi}{6} = \frac{\sqrt{3}}{2}$
 
 $\cos\frac{\pi}{3} = \frac{1}{2}$
 
-$\forall (a,b) \in \R^2$
+$\forall (a,b) \in \R$
 
 $\cos(a + b) = \cos a \cos b + \sin a \sin b$
 
@@ -46,7 +46,7 @@ $\sin \frac{\pi}{2} = 1$
 
 %$\sin(\frac{\pi}{2} + t) = -\cos(t)$
 
-$\forall (a,b) \in \R^2$
+$\forall (a,b) \in \R$
 
 $\sin(a + b) = \sin a \cos b + \sin b \cos a$
 
@@ -76,8 +76,20 @@ $\tan(a - b) = \frac{\tan(a) - \tan(b)}{1 + \tan(a)\tan(b)}$
 \subsection{Combinaisons}
 %TODO Complete subsection
 
-$\forall (a,b) \in \R^2$
+$\forall (a,b) \in \R$
 
 $\sin a \cos b = \frac{\sin(a + b) + \sin(a - b)}{2}$
 
+\langsection{Fonctions hyperboliques}{Hyperbolic functions}
 
+\subsection{cosh}
+
+$cosh\ x = \frac{e^x + e^{-x}}{2} = \frac{e^{2x} + 1}{2e^x} = \frac{1 + e^{-2x}}{2e^{-x}}$
+
+\subsection{sinh}
+
+$sinh\ x = \frac{e^x - e^{-x}}{2} = \frac{e^{2x} - 1}{2e^x} = \frac{1 - e^{-2x}}{2e^{-x}}$
+
+\subsection{tanh}
+
+$tanh\ x = \frac{sinh\ x}{cosh\ x} = \frac{e^x - e^{-x}}{e^x + e^{-x}} = \frac{e^{2x} - 1}{e^{2x} + 1}$