Legacy Document

Inside Macintosh: Operating System Utilities /

Chapter 3 - Mathematical and Logical Utilities / Mathematical and Logical Utilities Reference

Routines / Performing Calculations on Fixed-Point Numbers

FracSin

You can use the FracSin function to obtain a fast approximation of the sine of a Fixed number.

FUNCTION FracSin (x: Fixed): Fract;

x

The Fixed number expressed in radians, whose sine is to be calculated.

DESCRIPTION

The FracSin function returns the sine, expressed in radians, of the Fixed number x.

The approximation of Pi/4 used to compute the sine is the hexadecimal value 0.C910, making the approximation of Pi equal to 3.1416015625, while Pi itself equals 3.14159265.... Despite the approximation of Pi, the sine value obtained is usually correct to several decimal places.