blob: efd3a8cc871961485044a729454da12652a4903e (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
|
/*
asin(arg) and acos(arg) return the arcsin, arccos,
respectively of their arguments.
Arctan is called after appropriate range reduction.
*/
#include <math.h>
#include <errno.h>
static double pio2 = 1.570796326794896619231e0;
double
asin(double arg)
{
double temp;
int sign;
sign = 0;
if(arg < 0) {
arg = -arg;
sign++;
}
if(arg > 1) {
errno = EDOM;
return 0;
}
temp = sqrt(1 - arg*arg);
if(arg > 0.7)
temp = pio2 - atan(temp/arg);
else
temp = atan(arg/temp);
if(sign)
temp = -temp;
return temp;
}
double
acos(double arg)
{
if(arg > 1 || arg < -1) {
errno = EDOM;
return 0;
}
return pio2 - asin(arg);
}
|
