...
Run Format

Source file src/math/asin.go

Documentation: math

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package math
     6  
     7  /*
     8  	Floating-point arcsine and arccosine.
     9  
    10  	They are implemented by computing the arctangent
    11  	after appropriate range reduction.
    12  */
    13  
    14  // Asin returns the arcsine, in radians, of x.
    15  //
    16  // Special cases are:
    17  //	Asin(±0) = ±0
    18  //	Asin(x) = NaN if x < -1 or x > 1
    19  func Asin(x float64) float64
    20  
    21  func asin(x float64) float64 {
    22  	if x == 0 {
    23  		return x // special case
    24  	}
    25  	sign := false
    26  	if x < 0 {
    27  		x = -x
    28  		sign = true
    29  	}
    30  	if x > 1 {
    31  		return NaN() // special case
    32  	}
    33  
    34  	temp := Sqrt(1 - x*x)
    35  	if x > 0.7 {
    36  		temp = Pi/2 - satan(temp/x)
    37  	} else {
    38  		temp = satan(x / temp)
    39  	}
    40  
    41  	if sign {
    42  		temp = -temp
    43  	}
    44  	return temp
    45  }
    46  
    47  // Acos returns the arccosine, in radians, of x.
    48  //
    49  // Special case is:
    50  //	Acos(x) = NaN if x < -1 or x > 1
    51  func Acos(x float64) float64
    52  
    53  func acos(x float64) float64 {
    54  	return Pi/2 - Asin(x)
    55  }
    56  

View as plain text