real: add sin, cos and ln2 functions

crates/cross/src/real.rs

@@ -92,6 +92,12 @@ pub trait Real:
     fn powf(self, p: Self) -> Self;
     fn sqrt(self) -> Self;
     fn sin_cos(self) -> (Self, Self);
+    fn sin(self) -> Self {
+        self.sin_cos().0
+    }
+    fn cos(self) -> Self {
+        self.sin_cos().1
+    }
 
     fn min_max_or_undefined(self, other: Self) -> (Self, Self) {
         match self.partial_cmp(&other) {
@@ -127,6 +133,7 @@ pub trait Real:
     fn half() -> Self;
     fn pi() -> Self;
     fn two_pi() -> Self;
+    fn ln2() -> Self;
 
     /// Speed of light in a vacuum; m/s.
     /// Also equal to 1/sqrt(epsilon_0 mu_0)
@@ -172,6 +179,9 @@ macro_rules! decl_consts {
         fn two_pi() -> Self {
             $wrap(6.283185307179586)
         }
+        fn ln2() -> Self {
+            $wrap(0.6931471805599453)
+        }
 
         /// Speed of light in a vacuum; m/s.
         /// Also equal to 1/sqrt(epsilon_0 mu_0)
@@ -481,6 +491,9 @@ impl<T: Real> Real for Finite<T> {
     fn two_pi() -> Self {
         Self::from_primitive(T::two_pi())
     }
+    fn ln2() -> Self {
+        Self::from_primitive(T::ln2())
+    }
     fn c() -> Self {
         Self::from_primitive(T::c())
     }