[444] | 1 | |
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| 2 | /* @(#)z_acos.c 1.0 98/08/13 */ |
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| 3 | |
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| 4 | /* |
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| 5 | FUNCTION |
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| 6 | <<acos>>, <<acosf>>---arc cosine |
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| 7 | |
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| 8 | INDEX |
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| 9 | acos |
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| 10 | INDEX |
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| 11 | acosf |
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| 12 | |
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| 13 | SYNOPSIS |
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| 14 | #include <math.h> |
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| 15 | double acos(double <[x]>); |
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| 16 | float acosf(float <[x]>); |
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| 17 | |
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| 18 | DESCRIPTION |
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| 19 | |
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| 20 | <<acos>> computes the inverse cosine (arc cosine) of the input value. |
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| 21 | Arguments to <<acos>> must be in the range @minus{}1 to 1. |
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| 22 | |
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| 23 | <<acosf>> is identical to <<acos>>, except that it performs |
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| 24 | its calculations on <<floats>>. |
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| 25 | |
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| 26 | RETURNS |
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| 27 | @ifnottex |
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| 28 | <<acos>> and <<acosf>> return values in radians, in the range of 0 to pi |
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| 29 | . |
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| 30 | @end ifnottex |
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| 31 | @tex |
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| 32 | <<acos>> and <<acosf>> return values in radians, in the range of <<0>> t |
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| 33 | o $\pi$. |
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| 34 | @end tex |
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| 35 | |
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| 36 | If <[x]> is not between @minus{}1 and 1, the returned value is NaN |
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| 37 | (not a number) the global variable <<errno>> is set to <<EDOM>>, and a |
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| 38 | <<DOMAIN error>> message is sent as standard error output. |
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| 39 | |
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| 40 | You can modify error handling for these functions using <<matherr>>. |
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| 41 | |
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| 42 | |
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| 43 | QUICKREF |
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| 44 | ansi svid posix rentrant |
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| 45 | acos y,y,y,m |
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| 46 | acosf n,n,n,m |
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| 47 | |
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| 48 | MATHREF |
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| 49 | acos, [-1,1], acos(arg),,, |
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| 50 | acos, NAN, arg,DOMAIN,EDOM |
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| 51 | |
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| 52 | MATHREF |
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| 53 | acosf, [-1,1], acosf(arg),,, |
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| 54 | acosf, NAN, argf,DOMAIN,EDOM |
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| 55 | |
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| 56 | */ |
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| 57 | |
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| 58 | /***************************************************************** |
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| 59 | * Arccosine |
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| 60 | * |
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| 61 | * Input: |
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| 62 | * x - floating point value |
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| 63 | * |
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| 64 | * Output: |
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| 65 | * arccosine of x |
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| 66 | * |
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| 67 | * Description: |
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| 68 | * This routine returns the arccosine of x. |
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| 69 | * |
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| 70 | *****************************************************************/ |
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| 71 | |
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| 72 | #include "fdlibm.h" |
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| 73 | #include "zmath.h" |
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| 74 | |
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| 75 | #ifndef _DOUBLE_IS_32BITS |
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| 76 | |
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| 77 | double |
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| 78 | acos (double x) |
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| 79 | { |
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| 80 | return (asine (x, 1)); |
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| 81 | } |
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| 82 | |
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| 83 | #endif /* _DOUBLE_IS_32BITS */ |
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