Compute
cos(x) - 1.
var cosm1 = require( '@stdlib/math/base/special/cosm1' );Computes cos(x) - 1, where cos is the cosine of a number (in radians). This function should be used instead of manually calculating cos(x) - 1 when the argument is near unity.
var PI = require( '@stdlib/constants/float64/pi' );
var v = cosm1( 0.0 );
// returns 0.0
v = cosm1( PI/4.0 );
// returns ~-0.293
v = cosm1( -PI/6.0 );
// returns ~-0.134
v = cosm1( NaN );
// returns NaNvar uniform = require( '@stdlib/random/array/uniform' );
var logEachMap = require( '@stdlib/console/log-each-map' );
var PI = require( '@stdlib/constants/float64/pi' );
var cosm1 = require( '@stdlib/math/base/special/cosm1' );
var opts = {
'dtype': 'float64'
};
var x = uniform( 100, 0.0, 2.0*PI, opts );
logEachMap( 'cos(%0.4f) - 1 = %0.4f', x, cosm1 );#include "stdlib/math/base/special/cosm1.h"Computes cos(x) - 1, where cos is the cosine of a number (in radians). This function should be used instead of manually calculating cos(x) - 1 when the argument is near unity.
double out = stdlib_base_cosm1( 0.0 );
// returns 0.0
out = stdlib_base_cosm1( 3.141592653589793238 / 4.0 );
// returns ~-0.293The function accepts the following arguments:
- x:
[in] doubleinput value.
double stdlib_base_cosm1( const double x );#include "stdlib/math/base/special/cosm1.h"
#include <stdio.h>
int main( void ) {
const double x[] = { 0.0, 0.523, 0.785, 1.047, 3.14 };
double y;
int i;
for ( i = 0; i < 5; i++ ) {
y = stdlib_base_cosm1( x[ i ] );
printf( "cosm1(%lf) = %lf\n", x[ i ], y );
}
}@stdlib/math/base/special/cos: compute the cosine of a number.