math: special cases for Atan, Asin and Acos
Added tests for NaN and out-of-range values.
Combined asin.go and atan.go into atan.go.
R=rsc
CC=golang-dev
https://golang.org/cl/180065
diff --git a/src/pkg/math/asin.go b/src/pkg/math/asin.go
index a138aac..439673a 100644
--- a/src/pkg/math/asin.go
+++ b/src/pkg/math/asin.go
@@ -25,9 +25,9 @@
temp := Sqrt(1 - x*x)
if x > 0.7 {
- temp = Pi/2 - Atan(temp/x)
+ temp = Pi/2 - satan(temp/x)
} else {
- temp = Atan(x / temp)
+ temp = satan(x / temp)
}
if sign {
@@ -37,9 +37,4 @@
}
// Acos returns the arc cosine of x.
-func Acos(x float64) float64 {
- if x > 1 || x < -1 {
- return NaN()
- }
- return Pi/2 - Asin(x)
-}
+func Acos(x float64) float64 { return Pi/2 - Asin(x) }
