ObjectScript Reference
$ZSIN


Returns the trigonometric sine of the specified angle value.
Synopsis
$ZSIN returns the trigonometric sine of
n. The result is a signed decimal number ranging from 1 to 1 (see note).
$ZSIN(0) returns 0.
$ZSIN($ZPI/2) returns 1.
Note:
$ZSIN (like all trigonometric functions) calculates its values based on pi rounded to the number of available decimal digits. Therefore, the value returned by
$ZSIN($ZPI) is .000000000000000000462644 and
$ZSIN($ZPI*2) is –.00000000000000000092529. For this reason you should not perform limit tests comparing these returned values to 0.
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, and negative Pi is equivalent to Pi.
A nonnumeric string is evaluated as 0.
The following example permits you to compute the sine of a number:
READ "Input a number: ",num
IF $ZABS(num)>(2*$ZPI) { WRITE !,"number is a larger than 2 pi" }
ELSE {
WRITE !,"the sine is: ",$ZSIN(num)
}
QUIT
The following example compares the results from InterSystems IRIS fractional numbers (
$DECIMAL numbers) and
$DOUBLE numbers. In both cases, the sine of pi is a fractional number (not 0), but the sine of pi/2 is set to exactly 1:
WRITE !,"the sine is: ",$ZSIN($ZPI)
WRITE !,"the sine is: ",$ZSIN($DOUBLE($ZPI))
WRITE !,"the sine is: ",$ZSIN($ZPI/2)
WRITE !,"the sine is: ",$ZSIN($DOUBLE($ZPI)/2)
In the following example, all
$ZSIN functions return zero (0):
WRITE !,"the sine is: ",$ZSIN(0.0)
WRITE !,"the sine is: ",$ZSIN(0.0)
WRITE !,"the sine is: ",$ZSIN($DECIMAL(0.0))
WRITE !,"the sine is: ",$ZSIN($DOUBLE(0.0))
WRITE !,"the sine is: ",$ZSIN($DECIMAL(0.0))
WRITE !,"the sine is: ",$ZSIN($DOUBLE(0.0))
WRITE !,"the sine is: ",$ZSIN($DECIMAL(0.0))
WRITE !,"the sine is: ",$ZSIN($DOUBLE(0.0))
This is true on all platforms, including AIX.