#!/bin/ksh

e=2.71828182845904523
PI=3.14159265358979323

TORADIANS=$(( PI/180.0 )) # Correction for degrees to radians
TODEGREES=$(( 180.0/PI )) # Correction for radians to degrees

# SIN fixed to 8 decimal places.
Sin()
{
        typeset ANGLE var # Tell KSH ANGLE is local
        typeset SIN var # Also local

        ANGLE="$1"
        SIN=0.0

        while (( ANGLE < 0.0 ))
        do
                (( ANGLE += 360 ))
        done

        while (( ANGLE >= 360.0 )) # Too bad KSH doesn't have fmod
        do
                (( ANGLE -= 360.0 ))
        done

        (( ANGLE > 270.0 )) && (( ANGLE -= 360 ))
        (( ANGLE > 180.0 )) && ANGLE=$((-(ANGLE-180)))
        (( ANGLE > 90.0  )) && ANGLE=$(( 180 - ANGLE ))

        (( ANGLE *= TORADIANS ))  # Convert to radians

        # Series coefficients, for the sum of A to the $1 divided by $2 for each pair
        # Sets $1=1, $2=1.0, $3=3, $4=-6.0, etc
        set --  1       1.0             \
                3       -6.0            \
                5       120.0           \
                7       -5040.0         \
                9       362880.0        \
                11      -39916800       \
                13      6227020800.0

        while [ "$#" -gt 0 ]
        do
                # We DO need $ here since $1, $2, etc are special
                (( SIN += (ANGLE**$1)/$2 ))
                shift 2 # Discard the first two arguments
        done

        printf "%.8f\n" "$SIN"
}

# Test degrees.
for x in $( seq 0.0 15.0 360.0 )
do
        printf "%d\t" $x
        Sin $x
done