diff --git a/src/angle.rs b/src/angle.rs
index 94dbf05..3998c75 100644
--- a/src/angle.rs
+++ b/src/angle.rs
@@ -104,24 +104,22 @@ pub trait Angle where
     fn equiv(&self, other: &Self) -> bool {
         self.normalize() == other.normalize()
     }
+
+    fn sin(self) -> Self::Unitless;
+    fn cos(self) -> Self::Unitless;
+    fn tan(self) -> Self::Unitless;
+    fn sin_cos(self) -> (Self::Unitless, Self::Unitless);
+
+    #[inline] fn cot(self) -> Self::Unitless { Self::tan(self).recip() }
+    #[inline] fn sec(self) -> Self::Unitless { Self::cos(self).recip() }
+    #[inline] fn csc(self) -> Self::Unitless { Self::sin(self).recip() }
+
+    fn asin(a: Self::Unitless) -> Self;
+    fn acos(a: Self::Unitless) -> Self;
+    fn atan(a: Self::Unitless) -> Self;
+    fn atan2(a: Self::Unitless, b: Self::Unitless) -> Self;
 }
 
-#[inline] pub fn bisect<A: Angle>(a: A, b: A) -> A { a.bisect(b) }
-
-#[inline] pub fn sin<S: BaseFloat, R: Into<Rad<S>>>(theta: R) -> S { theta.into().s.sin() }
-#[inline] pub fn cos<S: BaseFloat, R: Into<Rad<S>>>(theta: R) -> S { theta.into().s.cos() }
-#[inline] pub fn tan<S: BaseFloat, R: Into<Rad<S>>>(theta: R) -> S { theta.into().s.tan() }
-#[inline] pub fn sin_cos<S: BaseFloat, R: Into<Rad<S>>>(theta: R) -> (S, S) { theta.into().s.sin_cos() }
-
-#[inline] pub fn cot<S: BaseFloat, R: Into<Rad<S>>>(theta: R) -> S { tan(theta.into()).recip() }
-#[inline] pub fn sec<S: BaseFloat, R: Into<Rad<S>>>(theta: R) -> S { cos(theta.into()).recip() }
-#[inline] pub fn csc<S: BaseFloat, R: Into<Rad<S>>>(theta: R) -> S { sin(theta.into()).recip() }
-
-#[inline] pub fn asin<S: BaseFloat, R: From<Rad<S>>>(s: S) -> R { rad(s.asin()).into() }
-#[inline] pub fn acos<S: BaseFloat, R: From<Rad<S>>>(s: S) -> R { rad(s.acos()).into() }
-#[inline] pub fn atan<S: BaseFloat, R: From<Rad<S>>>(s: S) -> R { rad(s.atan()).into() }
-#[inline] pub fn atan2<S: BaseFloat, R: From<Rad<S>>>(a: S, b: S) -> R { rad(a.atan2(b)).into() }
-
 macro_rules! impl_angle {
     ($Angle:ident, $fmt:expr, $full_turn:expr, $hi:expr) => {
         impl<S: BaseFloat> Angle for $Angle<S> {
@@ -148,6 +146,16 @@ macro_rules! impl_angle {
             #[inline] fn turn_div_3() -> $Angle<S> { let factor: S = cast(3).unwrap(); $Angle::full_turn() / factor }
             #[inline] fn turn_div_4() -> $Angle<S> { let factor: S = cast(4).unwrap(); $Angle::full_turn() / factor }
             #[inline] fn turn_div_6() -> $Angle<S> { let factor: S = cast(6).unwrap(); $Angle::full_turn() / factor }
+
+            #[inline] fn sin(self) -> S { let rad: Rad<S> = self.into(); rad.s.sin() }
+            #[inline] fn cos(self) -> S { let rad: Rad<S> = self.into(); rad.s.cos() }
+            #[inline] fn tan(self) -> S { let rad: Rad<S> = self.into(); rad.s.tan() }
+            #[inline] fn sin_cos(self) -> (S, S) { let rad: Rad<S> = self.into(); rad.s.sin_cos() }
+
+            #[inline] fn asin(a: S) -> $Angle<S> { Rad::new(a.asin()).into() }
+            #[inline] fn acos(a: S) -> $Angle<S> { Rad::new(a.acos()).into() }
+            #[inline] fn atan(a: S) -> $Angle<S> { Rad::new(a.atan()).into() }
+            #[inline] fn atan2(a: S, b: S) -> $Angle<S> { Rad::new(a.atan2(b)).into() }
         }
 
         impl<S: BaseFloat> Neg for $Angle<S> {
diff --git a/src/matrix.rs b/src/matrix.rs
index 03faba0..399e0a2 100644
--- a/src/matrix.rs
+++ b/src/matrix.rs
@@ -25,7 +25,7 @@ use rand::{Rand, Rng};
 use rust_num::{Zero, One};
 use rust_num::traits::cast;
 
-use angle::{Rad, sin, cos, sin_cos};
+use angle::{Angle, Rad};
 use approx::ApproxEq;
 use array::Array;
 use num::BaseFloat;
@@ -71,11 +71,11 @@ impl<S: BaseFloat> Matrix2<S> {
 
     #[inline]
     pub fn from_angle(theta: Rad<S>) -> Matrix2<S> {
-        let cos_theta = cos(theta.clone());
-        let sin_theta = sin(theta.clone());
+        let cos_theta = Rad::cos(theta);
+        let sin_theta = Rad::sin(theta);
 
-        Matrix2::new(cos_theta.clone(),  sin_theta.clone(),
-                     -sin_theta.clone(), cos_theta.clone())
+        Matrix2::new(cos_theta,  sin_theta,
+                     -sin_theta, cos_theta)
     }
 }
 
@@ -118,27 +118,27 @@ impl<S: BaseFloat> Matrix3<S> {
     /// Create a rotation matrix from a rotation around the `x` axis (pitch).
     pub fn from_angle_x(theta: Rad<S>) -> Matrix3<S> {
         // http://en.wikipedia.org/wiki/Rotation_matrix#Basic_rotations
-        let (s, c) = sin_cos(theta);
+        let (s, c) = Rad::sin_cos(theta);
         Matrix3::new(S::one(), S::zero(), S::zero(),
-                     S::zero(), c.clone(), s.clone(),
-                     S::zero(), -s.clone(), c.clone())
+                     S::zero(), c, s,
+                     S::zero(), -s, c)
     }
 
     /// Create a rotation matrix from a rotation around the `y` axis (yaw).
     pub fn from_angle_y(theta: Rad<S>) -> Matrix3<S> {
         // http://en.wikipedia.org/wiki/Rotation_matrix#Basic_rotations
-        let (s, c) = sin_cos(theta);
-        Matrix3::new(c.clone(), S::zero(), -s.clone(),
+        let (s, c) = Rad::sin_cos(theta);
+        Matrix3::new(c, S::zero(), -s,
                      S::zero(), S::one(), S::zero(),
-                     s.clone(), S::zero(), c.clone())
+                     s, S::zero(), c)
     }
 
     /// Create a rotation matrix from a rotation around the `z` axis (roll).
     pub fn from_angle_z(theta: Rad<S>) -> Matrix3<S> {
         // http://en.wikipedia.org/wiki/Rotation_matrix#Basic_rotations
-        let (s, c) = sin_cos(theta);
-        Matrix3::new( c.clone(), s.clone(), S::zero(),
-                     -s.clone(), c.clone(), S::zero(),
+        let (s, c) = Rad::sin_cos(theta);
+        Matrix3::new( c, s, S::zero(),
+                     -s, c, S::zero(),
                      S::zero(), S::zero(), S::one())
     }
 
@@ -151,18 +151,18 @@ impl<S: BaseFloat> Matrix3<S> {
     /// - `z`: the angular rotation around the `z` axis (roll).
     pub fn from_euler(x: Rad<S>, y: Rad<S>, z: Rad<S>) -> Matrix3<S> {
         // http://en.wikipedia.org/wiki/Rotation_matrix#General_rotations
-        let (sx, cx) = sin_cos(x);
-        let (sy, cy) = sin_cos(y);
-        let (sz, cz) = sin_cos(z);
+        let (sx, cx) = Rad::sin_cos(x);
+        let (sy, cy) = Rad::sin_cos(y);
+        let (sz, cz) = Rad::sin_cos(z);
 
-        Matrix3::new(                cy * cz,                 cy * sz,     -sy,
-                     -cx * sz + sx * sy * cz,  cx * cz + sx * sy * sz, sx * cy,
-                      sx * sz + cx * sy * cz, -sx * cz + cx * sy * sz, cx * cy)
+        Matrix3::new(cy * cz, cy * sz, -sy,
+                     -cx * sz + sx * sy * cz, cx * cz + sx * sy * sz, sx * cy,
+                     sx * sz + cx * sy * cz, -sx * cz + cx * sy * sz, cx * cy)
     }
 
     /// Create a rotation matrix from an angle around an arbitrary axis.
     pub fn from_axis_angle(axis: Vector3<S>, angle: Rad<S>) -> Matrix3<S> {
-        let (s, c) = sin_cos(angle);
+        let (s, c) = Rad::sin_cos(angle);
         let _1subc = S::one() - c;
 
         Matrix3::new(_1subc * axis.x * axis.x + c,
diff --git a/src/projection.rs b/src/projection.rs
index 4987c63..4aaee72 100644
--- a/src/projection.rs
+++ b/src/projection.rs
@@ -16,7 +16,7 @@
 use rust_num::{Zero, One};
 use rust_num::traits::cast;
 
-use angle::{Angle, Rad, tan, cot};
+use angle::{Angle, Rad};
 use matrix::Matrix4;
 use num::BaseFloat;
 
@@ -76,7 +76,7 @@ impl<S: BaseFloat> PerspectiveFov<S> {
     pub fn to_perspective(&self) -> Perspective<S> {
         let two: S = cast(2).unwrap();
         let angle = self.fovy / two;
-        let ymax = self.near * tan(angle);
+        let ymax = self.near * Rad::tan(angle);
         let xmax = ymax * self.aspect;
 
         Perspective {
@@ -100,7 +100,7 @@ impl<S: BaseFloat> From<PerspectiveFov<S>> for Matrix4<S> {
         assert!(persp.far    > persp.near, "The far plane cannot be closer than the near plane, found: far: {:?}, near: {:?}", persp.far, persp.near);
 
         let two: S = cast(2).unwrap();
-        let f = cot(persp.fovy / two);
+        let f = Rad::cot(persp.fovy / two);
 
         let c0r0 = f / persp.aspect;
         let c0r1 = S::zero();
diff --git a/src/quaternion.rs b/src/quaternion.rs
index f0816c3..3d57ef3 100644
--- a/src/quaternion.rs
+++ b/src/quaternion.rs
@@ -13,7 +13,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::f64;
 use std::fmt;
 use std::mem;
 use std::ops::*;
@@ -22,7 +21,7 @@ use rand::{Rand, Rng};
 use rust_num::{Float, One, Zero};
 use rust_num::traits::cast;
 
-use angle::{Angle, Rad, acos, sin, sin_cos, rad};
+use angle::{Angle, Rad};
 use approx::ApproxEq;
 use matrix::{Matrix3, Matrix4};
 use num::BaseFloat;
@@ -210,12 +209,12 @@ impl<S: BaseFloat> Quaternion<S> {
                 dot
             };
 
-            let theta: Rad<S> = acos(robust_dot.clone());
+            let theta = Rad::acos(robust_dot.clone());
 
-            let scale1 = sin(theta * (S::one() - amount));
-            let scale2 = sin(theta * amount);
+            let scale1 = Rad::sin(theta * (S::one() - amount));
+            let scale2 = Rad::sin(theta * amount);
 
-            (self * scale1 + other * scale2) * sin(theta).recip()
+            (self * scale1 + other * scale2) * Rad::sin(theta).recip()
         }
     }
 
@@ -238,22 +237,21 @@ impl<S: BaseFloat> Quaternion<S> {
 
         if test > sig * unit {
             (
-                rad(S::zero()),
-                rad(cast(f64::consts::FRAC_PI_2).unwrap()),
-                rad(two * qx.atan2(qw)),
+                Rad::zero(),
+                Rad::turn_div_4(),
+                Rad::atan2(qx, qw) * two,
             )
         } else if test < -sig * unit {
-            let y: S = cast(f64::consts::FRAC_PI_2).unwrap();
             (
-                rad(S::zero()),
-                rad(-y),
-                rad(two * qx.atan2(qw)),
+                Rad::zero(),
+                -Rad::turn_div_4(),
+                Rad::atan2(qx, qw) * two,
             )
         } else {
             (
-                rad((two * (qy * qw - qx * qz)).atan2(one - two * (sqy + sqz))),
-                rad((two * (qx * qy + qz * qw)).asin()),
-                rad((two * (qx * qw - qy * qz)).atan2(one - two * (sqx + sqz))),
+                Rad::atan2(two * (qy * qw - qx * qz), one - two * (sqy + sqz)),
+                Rad::asin(two * (qx * qy + qz * qw)),
+                Rad::atan2(two * (qx * qw - qy * qz), one - two * (sqx + sqz)),
             )
         }
     }
@@ -362,16 +360,16 @@ impl<S: BaseFloat> Rotation<Point3<S>> for Quaternion<S> {
 impl<S: BaseFloat> Rotation3<S> for Quaternion<S> {
     #[inline]
     fn from_axis_angle(axis: Vector3<S>, angle: Rad<S>) -> Quaternion<S> {
-        let (s, c) = sin_cos(angle * cast(0.5f64).unwrap());
+        let (s, c) = Rad::sin_cos(angle * cast(0.5f64).unwrap());
         Quaternion::from_sv(c, axis * s)
     }
 
     /// - [Maths - Conversion Euler to Quaternion]
     ///   (http://www.euclideanspace.com/maths/geometry/rotations/conversions/eulerToQuaternion/index.htm)
     fn from_euler(x: Rad<S>, y: Rad<S>, z: Rad<S>) -> Quaternion<S> {
-        let (s1, c1) = sin_cos(x * cast(0.5f64).unwrap());
-        let (s2, c2) = sin_cos(y * cast(0.5f64).unwrap());
-        let (s3, c3) = sin_cos(z * cast(0.5f64).unwrap());
+        let (s1, c1) = Rad::sin_cos(x * cast(0.5f64).unwrap());
+        let (s2, c2) = Rad::sin_cos(y * cast(0.5f64).unwrap());
+        let (s3, c3) = Rad::sin_cos(z * cast(0.5f64).unwrap());
 
         Quaternion::new(c1 * c2 * c3 - s1 * s2 * s3,
                         s1 * s2 * c3 + c1 * c2 * s3,
diff --git a/src/rotation.rs b/src/rotation.rs
index d30e556..9efd908 100644
--- a/src/rotation.rs
+++ b/src/rotation.rs
@@ -13,7 +13,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use angle::{Rad, acos};
+use angle::{Angle, Rad};
 use approx::ApproxEq;
 use matrix::{Matrix, SquareMatrix};
 use matrix::{Matrix2, Matrix3};
@@ -186,7 +186,7 @@ impl<S: BaseFloat> Rotation<Point2<S>> for Basis2<S> {
 
     #[inline]
     fn between_vectors(a: Vector2<S>, b: Vector2<S>) -> Basis2<S> {
-        Rotation2::from_angle(acos(a.dot(b)) )
+        Rotation2::from_angle(Rad::acos(a.dot(b)) )
     }
 
     #[inline]
diff --git a/src/vector.rs b/src/vector.rs
index 407602a..6b4fcf6 100644
--- a/src/vector.rs
+++ b/src/vector.rs
@@ -95,7 +95,7 @@ use rand::{Rand, Rng};
 
 use rust_num::{NumCast, Zero, One};
 
-use angle::{Rad, atan2, acos};
+use angle::{Angle, Rad};
 use approx::ApproxEq;
 use array::Array;
 use num::{BaseNum, BaseFloat, PartialOrd};
@@ -441,21 +441,21 @@ pub trait EuclideanVector: Vector + Sized where
 impl<S: BaseFloat> EuclideanVector for Vector2<S> {
     #[inline]
     fn angle(self, other: Vector2<S>) -> Rad<S> {
-        atan2(self.perp_dot(other), self.dot(other))
+        Rad::atan2(self.perp_dot(other), self.dot(other))
     }
 }
 
 impl<S: BaseFloat> EuclideanVector for Vector3<S> {
     #[inline]
     fn angle(self, other: Vector3<S>) -> Rad<S> {
-        atan2(self.cross(other).length(), self.dot(other))
+        Rad::atan2(self.cross(other).length(), self.dot(other))
     }
 }
 
 impl<S: BaseFloat> EuclideanVector for Vector4<S> {
     #[inline]
     fn angle(self, other: Vector4<S>) -> Rad<S> {
-        acos(self.dot(other) / (self.length() * other.length()))
+        Rad::acos(self.dot(other) / (self.length() * other.length()))
     }
 }