# cos, acos

Cosine, Arccosine

## cos

Cosine

Syntax: cos x, cos[x]

Returns the cosine of x, taken to be in radians. The result is between -1 and 1, or null if the argument is null or infinity.

q)cos 0.2
0.9800666
q)min cos 10000?3.14159265
-1f
q)max cos 10000?3.14159265
1f


## acos

Arccosine

Syntax: acos x, acos[x]

Returns the arccosine of x; that is, the value whose cosine is x. The result is in radians and lies between 0 and π. (The range is approximate due to rounding errors).

Null is returned if the argument is not between -1 and 1.

q)acos -0.4
1.982313