diff --git a/glm/detail/func_trigonometric.inl b/glm/detail/func_trigonometric.inl
index ca0858c5..4bb24b5c 100644
--- a/glm/detail/func_trigonometric.inl
+++ b/glm/detail/func_trigonometric.inl
@@ -113,7 +113,7 @@ namespace glm
 
 	// atan
 	template <typename genType>
-	GLM_FUNC_QUALIFIER genType atan(genType const & y, genType const & x)
+	GLM_FUNC_QUALIFIER genType atan(genType y, genType x)
 	{
 		GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559, "'atan' only accept floating-point input");
 
@@ -166,7 +166,7 @@ namespace glm
 		using std::asinh;
 #	else
 		template <typename genType>
-		GLM_FUNC_QUALIFIER genType asinh(genType const & x)
+		GLM_FUNC_QUALIFIER genType asinh(genType x)
 		{
 			GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559, "'asinh' only accept floating-point input");
 
@@ -185,7 +185,7 @@ namespace glm
 		using std::acosh;
 #	else
 		template <typename genType> 
-		GLM_FUNC_QUALIFIER genType acosh(genType const & x)
+		GLM_FUNC_QUALIFIER genType acosh(genType x)
 		{
 			GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559, "'acosh' only accept floating-point input");
 
@@ -206,7 +206,7 @@ namespace glm
 		using std::atanh;
 #	else
 		template <typename genType>
-		GLM_FUNC_QUALIFIER genType atanh(genType const & x)
+		GLM_FUNC_QUALIFIER genType atanh(genType x)
 		{
 			GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559, "'atanh' only accept floating-point input");