Compute the arctangent of an angle
#include <math.h> double atan( double x ); float atanf( float x ); long double atanl( long double x );
These functions compute the arctangent (in radians) of x.
The arctangent, in the range (-π/2, π/2). For finite values of |x| > 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", atan(.5) ); return EXIT_SUCCESS; }
produces the output:
0.463648
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |