ObjectScript Reference \$ZTAN

Returns the trigonometric tangent of the specified angle value.
Synopsis
`\$ZTAN(n)`
Parameter
 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
\$ZTAN returns the trigonometric tangent of n. The result is a signed decimal number.
Note:
\$ZTAN (like all trigonometric functions) calculates its values based on pi rounded to the number of available decimal digits. Therefore, the value returned by \$ZTAN(\$ZPI) is –.000000000000000000462644 and \$ZTAN(–\$ZPI) is .000000000000000000462644. For this reason you should not perform limit tests comparing these returned values to 0. \$ZTAN(0) is 0.
Parameter
n
An angle in radians ranging from 0 to 2 Pi. It can be specified as a value, a variable, or an expression.
A non-numeric string is evaluated as 0.
Examples
The following example permits you to compute the tangent of a number:
```   READ "Input a number: ",num
WRITE !,"the tangent is: ",\$ZTAN(num)
QUIT```
The following example compares the results from InterSystems IRIS fractional numbers (\$DECIMAL numbers) and \$DOUBLE numbers. In both cases, the tangent of 0 is exactly 0, but the tangent of pi is a negative fractional number (not exactly 0):
```  WRITE !,"the tangent is: ",\$ZTAN(0.0)
WRITE !,"the tangent is: ",\$ZTAN(\$DOUBLE(0.0))
WRITE !,"the tangent is: ",\$ZTAN(\$ZPI)
WRITE !,"the tangent is: ",\$ZTAN(\$DOUBLE(\$ZPI))
WRITE !,"the tangent is: ",\$ZTAN(1.0)
WRITE !,"the tangent is: ",\$ZTAN(\$DOUBLE(1.0))```