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Compute the arctangent of an angle
#include <math.h>
double atan( double x );
float atanf( float x );
- x
- The tangent for which you want to find the angle.
libm
Use the -l m option to
qcc
to link against this library.
These functions compute the arctangent (specified in radians) of x.
The arctangent, in the range (-π/2, π/2).
|
If an error occurs, these functions return 0, but this is also a valid
mathematical result.
If you want to check for errors, set
errno
to 0, call the function, and then check errno again.
These functions don't change errno if no errors occurred. |
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
int main( void )
{
printf( "%f\n", atan(.5) );
return EXIT_SUCCESS;
}
produces the output:
0.463648
ANSI,
POSIX 1003.1
Safety: | |
Cancellation point |
No |
Interrupt handler |
No |
Signal handler |
No |
Thread |
Yes |
acos(),
asin(),
atan2()
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