1 files changed, 15 insertions, 1 deletions
diff --git a/nuttx/libc/math/lib_asinh.c b/nuttx/libc/math/lib_asinh.c
index 7b573fcdd..5a30ac1aa 100644
--- a/nuttx/libc/math/lib_asinh.c
+++ b/nuttx/libc/math/lib_asinh.c
@@ -49,6 +49,20 @@
 #ifdef CONFIG_HAVE_DOUBLE
 double asinh(double x)
 {
-  return log(x + sqrt(x * x + 1));
+  double y;
+  double z = x * x;
+
+  if (z < 1E-9)
+    {
+      /* x - 1/6 * x^3 + 3/40 * x^5 - 5/112 * x^7 + ... */
+
+      y = x * (1 - z / 6.0);
+    }
+  else
+    {
+      y = log(x + sqrt(z + 1));
+    }
+
+  return y;
 }
 #endif