Compute the arccosine of an angle
#include <math.h> double acos( double x ); float acosf( float x ); long double acosl( long double x );
These functions compute the arccosine (in radians) of x.
The arccosine in the range (0, π). For finite values not in the range [-1,1], these functions return NaN. The return value for +/-Inf is NaN.
#include <stdio.h> #include <math.h> #include <stdlib.h> int main( void ) { printf( "%f\n", acos(.5) ); return EXIT_SUCCESS; }
produces the output:
1.047197
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |