From 8c26b49a394514f6bd71d353f9ee7de0181cc754 Mon Sep 17 00:00:00 2001
From: Stephen Chung <schungx@live.com>
Date: Wed, 10 Feb 2021 12:10:50 +0800
Subject: [PATCH] Change trig functions to take/return radians.

---
 RELEASES.md                |  1 +
 src/packages/math_basic.rs | 24 ++++++++++++------------
 tests/math.rs              |  4 ++--
 3 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/RELEASES.md b/RELEASES.md
index 473ad1d5..c1121f29 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -13,6 +13,7 @@ Bug fixes
 Breaking changes
 ----------------
 
+* Trigonometry functions now take radians and return radians instead of degrees.
 * `Dynamic::into_shared` is no longer available under `no_closure`. It used to panic.
 
 Enhancements
diff --git a/src/packages/math_basic.rs b/src/packages/math_basic.rs
index 06cd52ab..bc7f87c0 100644
--- a/src/packages/math_basic.rs
+++ b/src/packages/math_basic.rs
@@ -112,40 +112,40 @@ mod trig_functions {
     use crate::FLOAT;
 
     pub fn sin(x: FLOAT) -> FLOAT {
-        x.to_radians().sin()
+        x.sin()
     }
     pub fn cos(x: FLOAT) -> FLOAT {
-        x.to_radians().cos()
+        x.cos()
     }
     pub fn tan(x: FLOAT) -> FLOAT {
-        x.to_radians().tan()
+        x.tan()
     }
     pub fn sinh(x: FLOAT) -> FLOAT {
-        x.to_radians().sinh()
+        x.sinh()
     }
     pub fn cosh(x: FLOAT) -> FLOAT {
-        x.to_radians().cosh()
+        x.cosh()
     }
     pub fn tanh(x: FLOAT) -> FLOAT {
-        x.to_radians().tanh()
+        x.tanh()
     }
     pub fn asin(x: FLOAT) -> FLOAT {
-        x.asin().to_degrees()
+        x.asin()
     }
     pub fn acos(x: FLOAT) -> FLOAT {
-        x.acos().to_degrees()
+        x.acos()
     }
     pub fn atan(x: FLOAT) -> FLOAT {
-        x.atan().to_degrees()
+        x.atan()
     }
     pub fn asinh(x: FLOAT) -> FLOAT {
-        x.asinh().to_degrees()
+        x.asinh()
     }
     pub fn acosh(x: FLOAT) -> FLOAT {
-        x.acosh().to_degrees()
+        x.acosh()
     }
     pub fn atanh(x: FLOAT) -> FLOAT {
-        x.atanh().to_degrees()
+        x.atanh()
     }
 }
 
diff --git a/tests/math.rs b/tests/math.rs
index fa398c83..25bf1228 100644
--- a/tests/math.rs
+++ b/tests/math.rs
@@ -14,10 +14,10 @@ fn test_math() -> Result<(), Box<EvalAltResult>> {
     assert_eq!(engine.eval::<INT>("3 % 2")?, 1);
 
     #[cfg(not(feature = "no_float"))]
-    assert!((engine.eval::<FLOAT>("sin(30.0)")? - 0.5).abs() < 0.001);
+    assert!((engine.eval::<FLOAT>("sin(PI()/6.0)")? - 0.5).abs() < 0.001);
 
     #[cfg(not(feature = "no_float"))]
-    assert!(engine.eval::<FLOAT>("cos(90.0)")?.abs() < 0.001);
+    assert!(engine.eval::<FLOAT>("cos(PI()/2.0)")?.abs() < 0.001);
 
     #[cfg(not(feature = "only_i32"))]
     assert_eq!(