acos, asin, atan, atan2

Arguments

Returns

The result of the arc trigonometric function in radians.

Description

These functions perform the arc trigonometric functions arc cosine, arc sine, arc tangent, and arc tangent with 2 arguments. The atan2 function is equivalent to:

atan( y / x );

except that atan2 is able to correctly handle x and y values of zero.

Example

    Gamma> acos (0.5);
    1.0471975511965978534
    Gamma> asin (0.5);
    0.52359877559829892668
    Gamma> atan (2);
    1.107148717794090409
    Gamma> atan2 (1, 2);
    0.46364760900080609352
    Gamma> atan2 (1, 0);
    1.570796326794896558
    Gamma> atan2 (0, 2);
    0
    Gamma>  
    		

See Also

sin, cos, tan