From 01d29b92e61eb1091b02576c8b20e34f1c1484d2 Mon Sep 17 00:00:00 2001
From: "K. Lange" <klange@toaruos.org>
Date: Sat, 4 Sep 2021 13:41:27 +0900
Subject: [PATCH] libm: Hyperolibc trig functions

---
 libc/math/bad.c  | 15 ---------------
 libc/math/math.c | 13 +++++++++++++
 2 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/libc/math/bad.c b/libc/math/bad.c
index 2c4e3119..820eb9ec 100644
--- a/libc/math/bad.c
+++ b/libc/math/bad.c
@@ -15,11 +15,6 @@ double asin(double x) {
 	return 0.0;
 }
 
-double cosh(double x) {
-	BAD;
-	return 0.0;
-}
-
 double ldexp(double a, int exp) {
 	double out = a;
 	while (exp) {
@@ -44,13 +39,3 @@ double log2(double x) {
 	return 0.0;
 }
 
-double sinh(double x) {
-	BAD;
-	return 0.0;
-}
-
-double tanh(double x) {
-	BAD;
-	return 0.0;
-}
-
diff --git a/libc/math/math.c b/libc/math/math.c
index 89e81908..44bc406d 100644
--- a/libc/math/math.c
+++ b/libc/math/math.c
@@ -456,3 +456,16 @@ double frexp(double x, int *exp) {
 	memcpy(&out, &out_double, sizeof(double));
 	return out;
 }
+
+double cosh(double x) {
+	return (exp(x) + exp(-x)) / 2.0;
+}
+
+double sinh(double x) {
+	return (exp(x) - exp(-x)) / 2.0;
+}
+
+double tanh(double x) {
+	return (exp(2.0*x) - 1.0) / (exp(2.0*x) + 1.0);
+}
+