#! /bin/sh
# file: pltf G. Moody 24 February 2002
EXP=
XMIN=
XMAX=
DX=
case $# in
1) EXP="$1" ;;
2) EXP="$1"; XMIN=$2 ;;
3) EXP="$1"; XMIN=$2; XMAX=$3 ;;
4) EXP="$1"; XMIN=$2; XMAX=$3; DX=$4 ;;
esac
if [ "x$EXP" = "x" ]
then
cat <<!
This program produces a table of a function of x. It can understand
all of the normal arithmetic operators (use ^ for "to the power of"
and % for "the remainder of"), parentheses, and a few functions:
s(x) sine of x (where x is in radians)
c(x) cosine of x (where x is in radians)
a(x) arctangent of x (returns result in radians)
l(x) natural (base e) logarithm of x
e(x) exponential of x
j(n,x) n-th order Bessel function of x (where n is an integer)
sqrt(x) square root of x (x >= 0
!
echo -n "f(x) = "
read EXP
echo -n "Enter the minimum value of x [-50]: "
read XMIN
echo -n "Enter the maximum value of x [50]: "
read XMAX
echo -n "Enter the increment of x [1]: "
read DX
fi
if [ "x$XMIN" = "x" ]
then
XMIN=-50
fi
if [ "x$XMAX" = "x" ]
then
XMAX=50
fi
if [ "x$DX" = "x" ]
then
DX=1
fi
ftable "$EXP" $XMIN $XMAX $DX | \
bc -l | \
plt 0 1 -t "f(x) = $EXP" -x x -y "f(x)"