# \$ZCOS (ObjectScript)

Cosine function.

## Synopsis

```\$ZCOS(n)
```

### Argument

Argument Description
n An angle in radians ranging from Pi to 2 Pi (inclusive). Other supplied numeric values are converted to a value within this range.

## Description

\$ZCOS returns the trigonometric cosine of n. The result is a signed decimal number ranging from -1 to +1. \$ZCOS(0) returns 1. \$ZCOS(\$ZPI) returns -1.

## Argument

### n

An angle in radians ranging from Pi to 2 Pi (inclusive). It can be specified as a value, a variable, or an expression. You can specify the value Pi by using the \$ZPI special variable. You can specify positive or negative values smaller than Pi or larger than 2 Pi; InterSystems IRIS resolve these values to the corresponding multiple of Pi. For example, 3 Pi is equivalent to Pi, negative Pi is equivalent to Pi, and zero is equivalent to 2 Pi.

A non-numeric string is evaluated as 0. For evaluation of mixed numeric strings and non-numeric strings, refer to Strings As Numbers in Using ObjectScript.

## Examples

The following example permits you to compute the cosine of a number:

```   READ "Input a number: ",num
IF \$ZABS(num)>(2*\$ZPI) { WRITE !,"number is a larger than 2 pi" }
ELSE {
WRITE !,"the cosine is: ",\$ZCOS(num)
}
QUIT```

The following example compares the results from InterSystems IRIS fractional numbers (\$DECIMAL numbers) and \$DOUBLE numbers. In both cases, the cosine of 0 is exactly 1, the cosine of pi is exactly -1:

```  WRITE !,"the cosine is: ",\$ZCOS(0.0)
WRITE !,"the cosine is: ",\$ZCOS(\$DOUBLE(0.0))
WRITE !,"the cosine is: ",\$ZCOS(1.0)
WRITE !,"the cosine is: ",\$ZCOS(\$DOUBLE(1.0))
WRITE !,"the cosine is: ",\$ZCOS(\$ZPI)
WRITE !,"the cosine is: ",\$ZCOS(\$DOUBLE(\$ZPI))```