diff --git a/glm/gtx/quaternion.hpp b/glm/gtx/quaternion.hpp
index 84949d68..3c9e8b04 100644
--- a/glm/gtx/quaternion.hpp
+++ b/glm/gtx/quaternion.hpp
@@ -94,8 +94,7 @@ namespace glm
 	/// @see gtx_quaternion
     template <typename valType> 
 	detail::tquat<valType> exp(
-		detail::tquat<valType> const & q, 
-		valType const & exponent);
+		detail::tquat<valType> const & q);
 
 	//! Returns a log of a quaternion. 
 	///
diff --git a/glm/gtx/quaternion.inl b/glm/gtx/quaternion.inl
index b3880355..32155ce5 100644
--- a/glm/gtx/quaternion.inl
+++ b/glm/gtx/quaternion.inl
@@ -40,7 +40,7 @@ namespace glm
 		detail::tquat<T> const & s2, 
 		T const & h)
 	{
-		return mix(mix(q1, q2, h), mix(s1, s2, h), T(2) * h (T(1) - h));
+		return mix(mix(q1, q2, h), mix(s1, s2, h), T(2) * (T(1) - h) * h);
 	}
 
 	template <typename T> 
@@ -52,20 +52,19 @@ namespace glm
 	)
 	{
 		detail::tquat<T> invQuat = inverse(curr);
-		return ext((log(next + invQuat) + log(prev + invQuat)) / T(-4)) * curr;
+		return exp((log(next + invQuat) + log(prev + invQuat)) / T(-4)) * curr;
 	}
 
 	template <typename T> 
 	GLM_FUNC_QUALIFIER detail::tquat<T> exp
 	(
-		detail::tquat<T> const & q, 
-		T const & exponent
+		detail::tquat<T> const & q
 	)
 	{
 		detail::tvec3<T> u(q.x, q.y, q.z);
-		float a = glm::length(u);
-		detail::tvec3<T> v(u / a);
-		return detail::tquat<T>(cos(a), sin(a) * v);
+		float Angle = glm::length(u);
+		detail::tvec3<T> v(u / Angle);
+		return detail::tquat<T>(cos(Angle), sin(Angle) * v);
 	}
 
 	template <typename T>