Caché ObjectScript Reference
$ZCOS
[Home] [Back] [Next]
InterSystems: The power behind what matters   
Class Reference   
Search:    

Cosine function.
Synopsis
$ZCOS(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
$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.
Parameter
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; Caché 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.
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: ",$ZCOS(num)
        }
   QUIT
The following example compares the results from Caché fractional numbers ($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))
 
See Also