cos

Use the cos function in APL to compute the cosine of an angle expressed in radians. The function accepts any real number and returns a value in the range [-1, 1].

cos is useful in observability and log analysis when you need to encode time-of-day or other cyclic patterns as a continuous numeric feature. For example, you can combine cos and sin to represent hour-of-day as a pair of cyclic coordinates, which preserves the circular distance between hours for anomaly detection or grouping.

Usage

Syntax

cos(x)

Parameters

Returns

The cosine of x, a real number in the range [-1, 1].

Example

Use cos to compute the cosine of an angle in radians.

Query

print result = cos(pi())

Output

List of related functions

• sin: Returns the sine. Use sin and cos together to produce a two-dimensional cyclic encoding of angles.
• tan: Returns the tangent. Use it when you need the ratio of sine to cosine.
• acos: Returns the arc cosine. Use it as the inverse of cos.
• pi: Returns the constant π. Use it to compute angle values in radians.
• radians: Converts degrees to radians. Use it to prepare angle inputs before calling cos.

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