diff --git a/test/Vector3_test.cc b/test/Vector3_test.cc
index 275d173..7d5ee81 100644
--- a/test/Vector3_test.cc
+++ b/test/Vector3_test.cc
@@ -1,4 +1,5 @@
 #include <gtest/gtest.h>
+#include <math.h>
 #include <limits>
 #include "Vector3.h"
 
@@ -85,12 +86,12 @@ TEST(Vector3, Normalize) {
 	if (std::numeric_limits<float>::is_iec559) {
 		v1 = Vector3(FLOAT_INFINITY, FLOAT_INFINITY, FLOAT_INFINITY);
 		v = v1.normalized();
-		r = std::isnan(v.x) && std::isnan(v.y) && std::isnan(v.z);
+		r = isnan(v.x) && isnan(v.y) && isnan(v.z);
 		EXPECT_TRUE(r) << "v.normalized INFINITY INFINITY INFINITY";
 
 		v1 = Vector3(-FLOAT_INFINITY, -FLOAT_INFINITY, -FLOAT_INFINITY);
 		v = v1.normalized();
-		r = std::isnan(v.x) && std::isnan(v.y) && std::isnan(v.z);
+		r = isnan(v.x) && isnan(v.y) && isnan(v.z);
 		EXPECT_TRUE(r) << "v.normalized -INFINITY -INFINITY -INFINITY";
 
 	}
@@ -374,12 +375,12 @@ TEST(Vector3, Cross) {
 	if (std::numeric_limits<float>::is_iec559) {
 		v2 = Vector3(FLOAT_INFINITY, FLOAT_INFINITY, FLOAT_INFINITY);
 		v = Vector3::Cross(v1, v2);
-		r = std::isnan(v.x) && std::isnan(v.y) && std::isnan(v.z);
+		r = isnan(v.x) && isnan(v.y) && isnan(v.z);
 		EXPECT_TRUE(r) << "Cross(4 5 6, INFINITY INFINITY INFINITY)";
 
 		v2 = Vector3(-FLOAT_INFINITY, -FLOAT_INFINITY, -FLOAT_INFINITY);
 		v = Vector3::Cross(v1, v2);
-		r = std::isnan(v.x) && std::isnan(v.y) && std::isnan(v.z);
+		r = isnan(v.x) && isnan(v.y) && isnan(v.z);
 		EXPECT_TRUE(r) << "Cross(4 5 6, -INFINITY -INFINITY -INFINITY)";
 	}
 }
@@ -407,12 +408,12 @@ TEST(Vector3, Project) {
 	if (std::numeric_limits<float>::is_iec559) {
 		v2 = Vector3(FLOAT_INFINITY, FLOAT_INFINITY, FLOAT_INFINITY);
 		v = Vector3::Project(v1, v2);
-		r = std::isnan(v.x) && std::isnan(v.y) && std::isnan(v.z);
+		r = isnan(v.x) && isnan(v.y) && isnan(v.z);
 		EXPECT_TRUE(r) << "Project(4 5 6, INFINITY INFINITY INFINITY)";
 
 		v2 = Vector3(-FLOAT_INFINITY, -FLOAT_INFINITY, -FLOAT_INFINITY);
 		v = Vector3::Project(v1, v2);
-		r = std::isnan(v.x) && std::isnan(v.y) && std::isnan(v.z);
+		r = isnan(v.x) && isnan(v.y) && isnan(v.z);
 		EXPECT_TRUE(r) << "Project(4 5 6, -INFINITY -INFINITY -INFINITY)";
 	}
 }
@@ -440,12 +441,12 @@ TEST(Vector3, ProjectOnPlane) {
 	if (std::numeric_limits<float>::is_iec559) {
 		v2 = Vector3(FLOAT_INFINITY, FLOAT_INFINITY, FLOAT_INFINITY);
 		v = Vector3::ProjectOnPlane(v1, v2);
-		r = std::isnan(v.x) && std::isnan(v.y) && std::isnan(v.z);
+		r = isnan(v.x) && isnan(v.y) && isnan(v.z);
 		EXPECT_TRUE(r) << "ProjectOnPlane(4 5 6, INFINITY INFINITY INFINITY)";
 
 		v2 = Vector3(-FLOAT_INFINITY, -FLOAT_INFINITY, -FLOAT_INFINITY);
 		v = Vector3::ProjectOnPlane(v1, v2);
-		r = std::isnan(v.x) && std::isnan(v.y) && std::isnan(v.z);
+		r = isnan(v.x) && isnan(v.y) && isnan(v.z);
 		EXPECT_TRUE(r) << "ProjectOnPlane(4 5 6, -INFINITY -INFINITY -INFINITY)";
 	}
 }
@@ -470,12 +471,12 @@ TEST(Vector3, Angle) {
 	if (std::numeric_limits<float>::is_iec559) {
 		v2 = Vector3(FLOAT_INFINITY, FLOAT_INFINITY, FLOAT_INFINITY);
 		f = Vector3::Angle(v1, v2);
-		r = std::isnan(f);
+		r = isnan(f);
 		EXPECT_TRUE(r) << "Angle(4 5 6, INFINITY INFINITY INFINITY)";
 
 		v2 = Vector3(-FLOAT_INFINITY, -FLOAT_INFINITY, -FLOAT_INFINITY);
 		f = Vector3::Angle(v1, v2);
-		r = std::isnan(f);
+		r = isnan(f);
 		EXPECT_TRUE(r) << "Angle(4 5 6, -INFINITY -INFINITY -INFINITY)";
 
 	}
@@ -512,12 +513,12 @@ TEST(Vector3, SignedAngle) {
 	if (std::numeric_limits<float>::is_iec559) {
 		v2 = Vector3(FLOAT_INFINITY, FLOAT_INFINITY, FLOAT_INFINITY);
 		f = Vector3::SignedAngle(v1, v2, v3);
-		r = std::isnan(f);
+		r = isnan(f);
 		EXPECT_TRUE(r) << "SignedAngle(4 5 6, INFINITY INFINITY INFINITY)";
 
 		v2 = Vector3(-FLOAT_INFINITY, -FLOAT_INFINITY, -FLOAT_INFINITY);
 		f = Vector3::SignedAngle(v1, v2, v3);
-		r = std::isnan(f);
+		r = isnan(f);
 		EXPECT_TRUE(r) << "SignedAngle(4 5 6, -INFINITY -INFINITY -INFINITY)";
 
 	}