diff --git a/components/libc/minilibc/math.c b/components/libc/minilibc/math.c
index bcba6051a862beb82a14a47c6c8ba7ac0446b357..27315a428cc9902bf34392a6ff53563e59a39175 100644
--- a/components/libc/minilibc/math.c
+++ b/components/libc/minilibc/math.c
@@ -9,7 +9,6 @@
  */
 
 #define PRECISION 9
-#define M_PI 3.141592653589793238462643
 
 static double cos_off_tbl[] = {0.0, -M_PI/2., 0, -M_PI/2.};
 static double cos_sign_tbl[] = {1,-1,-1,1};
diff --git a/components/libc/minilibc/math.h b/components/libc/minilibc/math.h
index e2ce6f8e71911e60bb539e82f2d765b47050f98e..b436eb08b5a0e19b9e8b89a9a01494a41760e25e 100644
--- a/components/libc/minilibc/math.h
+++ b/components/libc/minilibc/math.h
@@ -1,4 +1,9 @@
-#ifndef __STDIO_H__
-#define __STDIO_H__
+#ifndef __MATH_H__
+#define __MATH_H__
+
+#define M_PI 3.141592653589793238462643
+
+double sin(double x);
+double cos(double x);
 
 #endif