$\chi$CAS(io)Bernard.Parisse@univgrenoblealpes.fr.fr2018, 2022 
Contents
 1 Introduction and installation
 2 First steps
 3 Common CAS commands
 4 Probabilities and statistics
 5 Graphics
 6 Programs
 7 The 2d editor.
 8 Managing sessions
 9 Keyboard shortcuts.
 10 Remarks
 11 More complete version for the CG50
 12 Copyright and Thanks to.
 13 Developer infos.
Abstract: This document explains how to run efficiently $\chi$CAS on some Casio calculators (CG10, CG20, CG50 and Fx9750GIII, Fx9860GIII). $\chi$CAS is a port of the Giac/Xcas computer algebra system (CAS) for these calculators.CAS are not allowed during exams in some countries, it is the user responsability to check the rules before running $\chi$CAS in an exam. The authors shall not be held responsible for misuse of $\chi$CAS in exam conditions.
This document is interactive, you can modify and run commands by clicking in the ok button or by hitting Enter.
1 Introduction and installation
$\chi$CAS is a port of the Giac/Xcas computer algebra system (CAS) for the following Casio calculators : CG10, CG20, CG50 and Fx9750GIII, Fx9860GIII. Two versions are available for the CG50, a light version that is the same as on CG10 and CG20 (in one file), and a more complete version in two files. The more complete version has more Xcas commands (like geometry commands), a 3d rendering engine, some additional apps (like a formal spreadsheet or a financial application) and a port of MicroPython 1.12 with more modules than the Casio port of MicroPython 1.09, cf. section 11.2.
1.1 Calculator
To install or update $\chi$CAS, get on your computer the file khicasen.g3a (CG10, 20, 50) or khicasen.g1a (Fx9750GIII, Fx9860GIII).
Connect the USB cable of the calculator, type F1 for USB key connection
and copy the file khicasen.g3a
(or khicasen.g1a
)
on the calculator“key”
then disconnect the calculatorkey from your computer and wait a few seconds.
For the complete version on the CG50, replace the file above by these 2 files khicas50.ac2 and khicas50.g3a.
1.2 Emulator
If you test on the emulator,
(PC,
Mac),
from the main menu of the calculator (MENU), go to Memory
then F3 (Import/Export), then F1 (Import files),
select the file khicasen.g3a
(or khicasen.g1a
),
type F1 to save to
the calculator root directory, confirm with F1 if you upgrade.
Be patient, the transfert will take several minutes. Once the transfert is finished, you should see the icon of Xcas in the main menu (a snowflake on the CG10/20/50).
If you want to run the complete version for the CG50, replace the file above by these 2 files khicas50.882 and emucas50.g3a.
Note that $\chi$CAS is not compatible with the simulator distributed
by Casio on USB keys in some countries, you must run the emulator.
Once installed, the Windows version of the emulator can be run under Linux with wine
by the following command
wine "C:\Program Files (x86)\CASIO\fxCG Manager PLUS Subscription for fxCG50series\fxCG_Manager_PLUS_Subscription_for_fxCG50series.exe" /n"fxCG Manager PLUS Subscription for fxCG50series" &
2 First steps
From the main menu (MENU), move the cursor to the Xcas icon and hit EXE. This opens the “shell” (or history) where you can write most Xcas commands.
For example, type
1/2+1/6
then EXE, you should see the result 2/3
displayed below.
You can copy a level from the history of commands by hitting the
up and down arrow keys (once or more) and EXE. Then you can
modify the command and run it with EXE. For example, up arrow twice,
EXE, replace 1/6
by 1/3
and hit EXE.
The last result is stored in ans()
, hit the Ans
calculator key (shift ()
) to get it.
It is recommended to store the result in a variable if you want
to reuse a result later. There are two ways to store a value in a
variable

rightstore with
=>
using the $\rightarrow$ key, for example2=>A
stores 2 in variable A. Now, every time you writeA
in a computation, it will be replaced by 2.  leftstore with
:=
(shift INS), for exampleA:=2
does the same as2=>A
.
The most popular Xcas commands are available from F1 (algebra)
and F2 (calculus), then from the Catalog, where
they are shortly explained with an example.
Hit F4 (cmds), choose a submenu,
for example Algebra
, hit EXE,
move the selection to a command, for example factor
.
Now F6 will display a short help with an example. Hit F2
to copy the example in the commandline.
You can run it as is (EXE) or modify it and run it (EXE) if
you want to factor another polynomial.
When a command returns an expression, it is displayed in 2d mode. You can move with the pad if the expression is larger than the display. Type shiftF3 or ALPHAF3 to modify the fontsize. Type EXIT to go back to the shell. The 2d view is in fact a 2d editor that will be explained later.
Now, try to type the command plot(sin(x))
.
Hint: type F4 (cmd), then select
Graphs
.
When a command returns a graph, it will be displayed in a 2d frame.
You can modify the displayed area with +
or 
(zoom in or out, ()
does a partial zoomout along $Oy$),
the cursor keys, /
(orthonormalisation of the frame),
*
(autoscale), VAR or OPTN is a switch to display or hide axis.
Type F1 (menu) to modify the graphic window settings Xmin, Xmax, Ymin, Ymax.
Type EXIT to go back to the shell.
The KhiCAS File menu (F6) has an item Clear
that will erase
the display. This will not clear the variables, to achieve that
type VARS
, select the last item (restart
)
and confirm with EXE.
Hit MENU to leave $\chi$CAS. If you launch another application, the variables and history will be saved, they will be restored if you come back to $\chi$CAS. First time save is sometimes slow (10 to 20 seconds), next save will run faster.
3 Common CAS commands
3.1 Expand and factor
From F4 commands catalog, select Algebra
, or type F1.

factor
: factorization. Shortcut=>*
($\rightarrow$ key then *), for example
. Runcfactor
to factor over $\C$. partfrac
: expands a polynomial or performs partial fraction expansion over a fraction. Shortcut=>+
($\rightarrow$ then + key), for example
or
.simplify
: tries to simplify an expression. Shortcut=>/
($\rightarrow$ key then /), for example
ratnormal
: rewrite as an irreducible fraction.
3.2 Calculus
From F4 commands catalog, select Calculus
, or type F2

diff
: derivative. Shortcut'
for derivative with respect to $x$, example
and
are equivalent. For $n$thderivative, add $n$, for example 3rd derivative
. integrate
: antiderivative (1 or 2 or 4 arguments) for example
or
for $\int \frac{1}{t^41} \ dt$
Defined integration with 4 arguments, for example
computes $\int_0^\pi \sin(x)^4 \ dx$. For an approximate computation, enter one boundary as an approx number, for example
limit
: limit of an expression. Example
tabvar
: table of variations of an expression. for example
one can check with the graph
taylor
andseries
: Taylor expansion or asymptotic serie expansion, for example
Addpolynomial
if you do not want to have the remainder term.sum
: discrete summation, for example
computes $\sum_{k=1}^n k^2$,
computes the sum and rewrites it factored.
3.3 Solvers
From F4 commands catalog, select Solve
.

solve
solves an equation exactly. Takes the variable to solve for as second argument, unless it isx
, for example
.
If exact solving fails, runfsolve
for approx solving, either with an iterative method starting with a guess
, or by dichotomy
.
For complex solutions, runcsolve
.
It is possible to restrict solutions using assumptions on the variable, for example
then
. solve
can also solve (simple) polynomial systems, enter a list of equations as 1st argument and a list of variables as 2nd argument, for example intersection of a circle and a line:
 Run
linsolve
to solve linear systems. enter a list of equations as 1st argument and a list of variables as 2nd argument, example:
 Run
desolve
to solve exactly a differential equation. for example, to solve $y'=2y$, typedesolve(y'=2y)
.
Another example with an initial condition:
desolve([y'=2y,y(0)=1],x,y)
Runodesolve
for approx solving orplotode
for a graphic representation of the approx. solution. rsolve
solves some recurrence relations $u_{n+1}=f(u_n,...)$, for example to solve the arithmeticogeometric recurrence $u_{n+1}=2u_n+3, u_0=1$, type:
3.4 Arithmetic
When required, the distinction between integer arithmetic
and polynomial arithmetic is done by a prefix i
for
integer commands. For example ifactor
for integer factorization
and factor
for polynomial factorization
(or cfactor
for polynomial factorization over $\C$).
Some commands work for integers and polynomials, like
gcd
and lcm
.
3.4.1 Integers
From F4 catalog, select Arithmetic, Crypto
. Shortcut
shift S$\leftrightarrow$D

iquo(a,b)
,irem(a,b)
quotient and remainder of euclidean division of two integers.
isprime(n)
checks whether $n$ is prime. This is a probabilisitic test for large values of $n$.
ifactor(n)
factorizes an integer (not too large, since algorithms used are trial division and Pollard$\rho$, there is no space left in memory for quadratic sieve), for example
Shortcut $\rightarrow$ then * (=>*
)gcd(a,b)
,lcm(a,b)
GCD and LCM of two integers or polynomials.
iegcd(a,b)
returns 3 integers $u,v,d$ such that $au+bv=d$ where $d$ is the GCD of $a$ et $b$, $u<b$ and $v<a$.
ichinrem([a,m],[b,n])
returns (if possible) $c$ such that $c=a \pmod m$ and $c=b \pmod n$ (if $m$ are $n$ coprime, $c$ exists).
powmod(a,n,m)
returns $a^n \pmod m$ computed by the fast modular powering algorithm
asc
converts a string to a list of ASCII code,char
converts back a list to a string. These commands may be used to easily write cryptographic algorithms with string messages.
3.4.2 Polynomials
From F4 catalog, select Polynomials
.
The default variable is $x$, otherwise you can specify it as last
optional argument. For example degree(x^2*y)
or degree(x^2*y,x)
return 2,
degree(x^2*y,y)
returns 1.

coeff(P,n)
coefficient of $x^n$ in $P$,lcoeff(P)
leading coefficient of $P$, for example
degre(P)
degree of polynomial $P$
quo(P,Q)
,rem(P,Q)
quotient and remainder of euclidean division ofP
byQ
proot(P)
: approx. roots of $P$ (all roots, real and complex)
Graphic representation
interp(X,Y)
: for two lists of the same size, returns the interpolating polynomial $P$ such that $P(X_i)=Y_i$.
Graphic representation
resultant(P,Q)
: resultant of polynomials $P$ and $Q$
hermite(x,n)
: $n$th Hermite polynomial (orthogonal for the density $e^{x^2}dx$ on $\R$)laguerre(x,n,a)
: $n$th Laguerre polynomiallegendre(x,n)
: $n$th Legendre polynomial (orthogonal for the density $dx$ on $[1,1]$)tchebyshev1(n)
andtchebyshev2(n)
Tchebyshev polynomials of 1st and 2nd kind defined by : $T_n(\cos(x))=\cos(nx), \quad U_n(\cos(x))\sin(x)=\sin((n+1)x)$
3.5 Linear algebra, vectors, matrices
Xcas does not make distinction between vectors and lists. For example,
v:=[1,2]; w:=[3,4]
onload
defines 2 vectors $v$ and $w$, then dot
will compute
the scalar product of $v$ and $w$:
A matrix is a list of lists of the same size.
You can enter a matrix element by element using the
matrix editor (shiftMATR EXE or F6 0). Enter a new variable
name to create a new matrix
or the name of an existing variable to edit a matrix.
The ,
key may be used to insert a line or column, and
the DEL
key erases the line or column of the selection
(press UNDO
if you want to go one step back).
For small matrices, it is also convenient to enter them directly in the
commandline, for example to define
$A=\left(\begin{array}{cc} 1 & 2 \\ 3 & 4 \end{array}\right)$
type
A:=[[1,2],[3,4]]
onload
or
It is recommended to store matrices in variables!
If a matrix is defined by a formula, then it’s better to use the
matrix
command (shiftMATR EXE AC), for example:
returns the matrix where coefficient line $j$ and column $k$
is $\frac{1}{j+k+1}$ (beware, indices begin at 0).
Run idn(n)
to get the identity matrix of order $n$
and ranm(n,m,law,[parameter])
to
get a matrix with random coefficients with dimensions $n,m$.
for example
For basic arithmetic on matrices, use keyboard operators
(+  *
, inverse). Otherwise, open catalog and
select Matrices

eigenvalues and eigenvectors of matrix $A$.
finds the Jordan normal form of matrix $A$, returns matrices $P$ and $D$ such that $P^{1}AP=D$, with $D$ upper triangular (diagonal if $A$ is diagonalizable)
computes matrix $A$ to the $k$th power, where $k$ is symbolic.rref
: row reduction to echelon formlu
: $LU$ factorization of matrix $A$, returns a permutation $P$ and two matrices $L$ (lower) and $U$ (upper) such that $PA=LU$. The result of
may be passed as an argument to the command
to solve a system $Ax=b$ by solving two triangular systems (in $O(n^2)$ instead of $O(n^3)$).qr
$QR$ factorization of matrix $A$, $Q$ is orthogonal and $R$ upper triangular, $A=QR$.svd(A)
singular value decomposition of matrix $A$ returns $U$ orthogonal, $S$ vector of singular values, $Q$ orthogonal such thatA=U*diag(S)*tran(Q)
.
The ratio of the largest and the smallest singular value of $S$ is the condition number of $A$ relative to the Euclidean norm.
4 Probabilities and statistics
4.1 Random numbers
From F4 catalog, select Probabilities
then
(real in $[0,1)$) or
(integer between 1 and $n$).
Other commands with prefix rand
are available, followed
by the name of the law, for example randbinomial(n,p)
returns a random integer according to binomial law of parameters $n,p$.
For a random vector or matrix, run
ranv
or ranm
(from Alglin, Matrice
submenu),
for example for a vector with 10 random
reals according to normal law (mean 0, stddev 1), type
4.2 Probabilities
From F4 catalog, select Probabilities
(8).
There you will find a few distribution laws:
binomial
, normald
, exponentiald
and uniformd
. Other distribution must be keyed in:
chisquared
, geometric
, multinomial
,
studentd
, fisherd
, poisson
.
To get the cumulated distribution function, enter the law name then
the _cdf
suffix (shortcut: select
cdf
in the catalog at the end and press F1).
Inverse cumulated distribution function follows the same principle
with _icdf
suffix (shortcut:
select cdf
in the catalog and press F2).
Example : find the centered interval $I$ for the normal law of
mean 5000, standard deviation 200, such that the probability
to be outside $I$ is 5%
4.3 1d statistics
The statistic functions are taking lists as arguments, for example
l:=[9,11,6,13,17,10]
onload
From F4 catalog, select Statistics
:

: arithmetic mean of a list 
: standard deviation of a list.
Run
to get an unbiaised estimate of the standard deviation of a population from a samplel

,
,
returns respectivly the median, first and third quartile of a list.
For 1d statistics with frequencies, replace l
by two lists of the same length, the first list being the
values of the serie, the second list the frequencies.
For graphic representations, open catalog, Graphic
and select histogram
or barplot
.
4.4 2d statistics
From F4 catalog, select Statistics
:

correlation(X,Y)
: correlation of two lists $X$ and $Y$ of the same length. covariance(X,Y)
:: covariance of two lists $X$ and $Y$ of the same length. regression computations:
run commands with suffix
_regression(X,Y)
, for examplelinear_regression(X,Y)
returns coefficients $m,p$ of the linear regression line $y=mx+p$. linear_regression_plot(X,Y)
and all commands of suffix_regression_plot
will display the line (or curve) of the regression. These commands will also print the $R^2$ coefficient that give information on the quality of adjustment ($R^2$ near 1 is good).
5 Graphics
From F4 catalog, select Graphics
(shortcut 7).

plot(f(x),x=a..b)
plot expression $f(x)$ for $x\in [a,b]$. Discretization option:xstep=
, for example
Default is 384 evaluations per plot (one per horizontal pixel). plotseq(f(x),x=[u0,a,b])
webplot for a recurrent sequence $u_{n+1}=f(u_n)$ of first term $u_0$, for example if $u_{n+1}=\sqrt{2+u_n}, u_0=6$, with a plot on $[0,7]$
plotparam([x(t),y(t)],t=tm..tM)
parametric plot $(x(t),y(t))$ for $t\in [t_m,t_M]$. Discretization option:tstep=
. Example
plotpolar(r(theta),theta=a..b)
polar plot of $r(\theta)$ for $\theta \in [a,b]$, for example
plotlist(l)
: plot a listl
, i.e. draws a polygonal line with vertices $(i,l_i)$ (index $i$ starts at 0).
plotlist([X1,Y1],[X2,Y2],...)
polygonal line with vertices the points of coordinates $(X_i,Y_i)$scatterplot(X,Y)
,polygonscatterplot(X,Y)
for two listsX,Y
of the same size, draws the points or a polygonal line of vertices $(X_i,Y_i)$histogram(l,class_min,class_size)
plots the histogram of data inl
, class sizeclass_size
, first class starts atclass_min
. Example: check the random generator quality
plotcontour(f(x,y),[x=xmin..xmax,y=ymin..ymax],[l0,l1,...])
plot implicit curves $f(x,y)=l_0, f(x,y)=l_1,...$.plotfield(f(t,y),[t=tmin..tmax,y=ymin..ymax])
plot the field of tangents for the differential equation $y'=f(t,y)$. Add the optional last parameter,plotode=[t0,y0]
to plot simultaneously the solution with initial condition $y(t_0)=y_0$. Example $y'=\sin(ty)$ for $t \in [3,3]$ and $y \in [2,2]$
N.B.:plotode
may be used outside ofplotfield
.
For simultaneous plots, write commands separated by ;
For display options, press the OPTN key:

display=color
color option: select a color then press F2, for example
display=line_width_2
todisplay=line_width_8
: change segments width (including inside polygonal line used to plot a curve). Simultaneous display options should be added with+
. For exampledisplay=red+line_width_2
 Circles and rectangles with edges parallel to the coordinate
axis may be filled with
display=filled
(this attribute might be added to other attributes)  If you want to define the display window (overwriting
the autoscale computation), select
gl_x
or/andgl_y
and add an $x$ or $y$ interval, for example
Note thatgl_
commands must preced the plotting command.  If you want to remove axes, select
axes
and press F2 (axes=0
). Likegl_
commands,axes=0
must preced the plotting command. Axes can be removed interactively when the graph screen is displayed by pressing VARS.
6 Programs
You can program either with Xcaslike syntax (English or French) or with Pythonlike syntax.
Example : function defined by an algebraic expression
nom_fonction(parametres):=expression
for example simple confidence interval for a frequency $p$ in a sample
of size $N$
Test
Second example : more precise confidence interval for a frequency $p$
in a sample of size $N$:
To avoid computing twice the same quantity, one can insert
a local variable.
The commandline is not well adapted to write these kinds
of functions. For non algebraic functions, it is best to run the
program editor. Press F6, select Script Editor, clear the editor if it
is not empty (F6 Clear) and
type with the help of test (F1), loop (F2)
for programming structures
the following program, in Xcas syntax:
or in Python syntax:
Type EXE to check the syntax. Once
the program is correct, save it (F6 2), then type EXIT. Now you
can call your program from the commandline like this
f(0.5,30)
Third example : a loop printing integer squares
from 1 to $n$ in Python syntax.
Check that Python syntax is enabled in the F6 or shiftSETUP menu,
if it is not checked, check it.
Open F6 Script Editor, if there is some old script source,
clear it (F6 Clear).
Select f(x):=
from F2 (or from F4, Program, function def),
you should get def f(x):
.
Replace x
by n
(press F5 to lock the keyboard in alpha lowercase), move to the end of
the line and press shiftEXE to input a newline.
Type ShiftPRGM then 3 for
, then F5 J space alpha, then
ShiftPRGM then 6 in range(a,b)
. Type 1,n+1)
then F1 (:
). Type shiftEXE to insert a newline
then Alpha SPACE,
F4 (Cmds), EXE (1 All
), P, R select print
with the cursor
then type EXE, type j,j^2)
then EXE.
def f(n): for j in range(1,n+1): print(j,j^2)
Inside Xcas ^
means power, **
is also accepted like in
Python.
Now, type EXE (or F6, select 1. Check syntax
). If syntax is correct,
you will see Success
in the status line. Otherwise, the
first error line number and token will be displayed and cursor will
be positionned at the line where the error was detected. Note that
the error may be before this line but it was only detected later. Note
also that if you are using Python syntax compatibility, programming
structures are translated into Xcas, errors are displayed after
translation, therefore you might see token errors like end
that were added by the translator.
If the program is correct, you can save it with the F6 menu (save or save as).
You can run it from the commandline by pressing EXIT then for
example f(10)
should display all squares from 1 to 10.
The turtle is a nice way to learn programming. The turtle is a small
robot that you can move, it handles a pen that marks its path.
Type F6, Script Editor, then F6 Clear. Type shiftQUIT select
efface
which means clear the screen. You can
access to the turtle commands using shiftQUIT (move the cursor to
a command and press F6 for help). For example try avance
(forward). Checking the syntax (EXE)
will display the turtle window moves.
You can enter several moves in your script, and organize them
inside tests, loops and functions.
For example:
function square(n) repete(4,avance n,tourne_gauche); ffunction:; efface; for n from 1 to 10 do square(10*n); od;
Another example of non algebraic function: the euclidean algorithm
to compute the GCD of two integers.
Press shiftEXE to insert a newline. !
is in the
submenu Programmation_cmds
(11, shortcut $X,\theta,T$)
or in the test F1 menu.
Xcas syntax
function pgcd(a,b) while b!=0 do a,b:=b,irem(a,b); od; return a; ffunction
Python syntax
def pgcd(a,b): while b!=0: a,b=b,a % b return a
Check with
If your program has runtime errors or if you want
to see it run step by step, run debug
on it,
for example
debug(pgcd(12345,3425))
Unlike adaptations of MicroPython by calculator manufacturers (including
Casio), the Python syntax in Xcas is fully integrated.
You can therefore use all Xcas commands and data types in your programs.
This corresponds approximatively to importing Python modules
math
, cmath
, random
,
scipy
, numpy
, turtle
, giacpy
.
There is also a small
pixelised graphic commands set
(set_pixel(x,y,c)
, set_pixel()
to synchronize
display, clearscreen()
, draw_line(x1,y1,x2,y2,c)
,
draw_polygon([[x1,y1],[x2,y2],...],c)
,
draw_rectangle(x,y,w,h,c)
, draw_circle(x,y,r,c)
,
the color+width+filled c
parameter is optional,
draw_arc(x,y,rx,ry,t1,t2,c)
draws an ellipsis arc).
And you can somewhat replace matplotlib
with graphic commands of $\chi$CAS
(point
, line
, segment
, circle
,
barplot
, histogram
and all ...plot...
commands). Plus you have natural access to data types
like rationnals or expressions, and you can run CAS commands on them.
The complete list of commands available on the calculator
is given in appendix. For documentation on commands not listed
in the catalog categories, please refer to Xcas documentation.
7 The 2d editor.
If a computation returns an expression, it will be displayed in the 2d expression editor. This also happens if you press F3 when the selected level is an expression, or if you press F3 from the commandline if the line is empty or contains a syntaxically correct expression.
Once the 2d editor is open, the expression is displayed in full screen and all or part of the expression is selected. One can run a command on the selection (from the menus or from the keyboard), or edit (in 1d mode) the selection. This is an efficient way to rewrite expressions or edit them.
Example 1 : enter $\lim_{x \rightarrow 0} \frac{\sin(x)}{x}$ From an empty commandline, type F3 (view), you should see 0 selected. Type x then EXE, this will replace 0 by x selected. Type SIN, now $\sin(x)$ should be selected. Type the division key (above ), you should see $\frac{\sin(x)}{0}$ with 0 selected, type x then EXE, you should now see $\frac{\sin(x)}{x}$ with x (below the fraction) selected. Type the up arrow key, now $\frac{\sin(x)}{x}$ should be selected. Now type F2 4 (for limit). The expression is ready to eval, type EXE to copy it to the commandline and EXE again to eval it. For the same limit at $+\infty$, before leaving the 2d editor with EXE, move the selection with the right arrow key, then type F1 8 (oo) EXE.
Example 2 :
$\int_0^{+\infty} \frac{1}{x^4+1} \ dx$
From an empty commandline, type F3 (view), then F2 3 (integrate),
you should see:
$\int_0^1 0 \ dx$
with $x$ selected. We must modify the 1 (upper bound) and
the 0 (integrand). Press left arrow key, this will select the
integrand 0, type 1/(x^4+1)
EXE, then left arrow key F1 8 EXE.
Type again EXE to copy to commandline, EXE again to run the computation,
the result will be displayed in the 2d editor, EXE will leave the 2d
editor, with the integral and its value in the history.
Example 3 : compute and simplify
$\int \frac{1}{x^4+1} \ dx$
From an empty commandline, type F3 (view), then F2 3 (integrate),
you should see
$\int_0^1 0 \ dx$
Move the selection to the lower bound 0 (right arrow key),
type DEL, you should see
$\int 0 \ dx$
selected. With the down arrow key, select 0, type 1/(x^4+1)
EXE,
EXE copy to the commandline, EXE to run the compuation, the result
is now displayed in the 2d editor.
With the arrow key, select one of the arctangent, type F1 EXE (simplify),
this will make a partial simplification, do the same on the second
arctangent.
For a more complete simplification, we will collect the logarithms.
The first step is to exchange two terms of the main sum so that the
logarithms are grouped. Select one of the logarithm with the arrow keys,
then type
 CG10,20,50 : shiftleft or right arrow key
 fx9860GIII: F5 left or right arrow key, then ALPHA
this will exchange the selection with the right or left sibling.
Now type ALPHA right or left arrow key to extend the selection adding
the right or left sibling. Once the two logarithm terms are selected,
press F1 2 EXE (factor), decrease the selection to the numerator,
type F4 EXE (All), type the letters l, n, c, this moves in the
catalog to the first command beginning with lnc
, select
lncollect
, EXE and F6 (eval).
8 Managing sessions
8.1 Modifying a session
With the up/down cursor keys, you can move in the history, the current level is printed with reverse colors.
You can move one level in another position with ALPHAup and ALPHAdown. You can delete a level with the DEL key (the level is copied into the clipboad).
You can modify an existing level with F3 or ALPHAF3. With F3, the 2d
editor is called if the level is an expression, with ALPHAF3 the level
is edited in the text (program) editor. Type EXIT if you want to cancel
modifications, or EXE if you confirm the modifications. If you confirm
the modifications, the commandlines below the current level will
automatically be reevaled. This way, if you modify for example
a level like A:=1
, all levels below that depend on the value
of A
will be up to date. If you want to do that several times,
it is best to introduce a parameter with the F6 Parameter wizzard. Then
pressing + or  on the assume(...)
or parameter
level
will modify the value of the parameter (press * or / for faster move).
8.2 Variables
Press VARS to see which variables are assigned to a value. Select a variable
name, press EXE to copy it to the commandline, DEL will input the command
that erases the variable (confirm with EXE). restart
will
purge all variables at once (press AC/ON
to clear the history
and start a fresh new session). assume
is a command to
make assumptions on a variable, like assume(x>5)
(>
can be accessed from the shiftPRGM menu).
8.3 Archiving and exchanging with Xcas
On the calculator, go back to the history (type EXIT if you are in the
programming editor or the 2d expression editor).
From the F6 menu, you can save/restore sessions in the
calculator flash memory. Files have the xw
extensions. They
can be copied to your computer (connect the calc, choose F1 USB key),
and there they may be opened with Xcas or Xcas for Firefox.
From Xcas, choose the File menu then Open file, then select
all type of files and open the session file.
From
Xcas for Firefox, press the Load button.
Conversely you can save a session from Xcas (choose File, Export to Khicas) or from Xcas for Firefox (choose Export at the right of the session name).
9 Keyboard shortcuts.
 F1 to F3 : depends on mode (Python/Xcas) and shift/alpha state, see labels
 F4: commands catalog.
 F5: uppercase to lowercase switch. If alpha mode is not active, locks the keyboard in alpha lowercase.
 F6: File menu
 cursor down from shell or shift fraction key from program editor (G key): completion/online help
()
in the text editor: returns the_
character. shift PRGM: programming commands or characters
 OPTN: all options
 shiftQUIT: turtle commands
 shiftList: create or edit a list, list commands
 shiftMat: create or edit a matrix, matrix commands
 S$\leftrightarrow$D key: real number commands
 yellow shifted S$\leftrightarrow$D key: integer commands
 angle key: complex commands
 yellow shifted fraction: plot commands
 fraction key: special characters/proba in history, indentation in text editor
 red r key:
abs
 red $\theta$ key:
arg
In programming editor
 shiftcursor key: move to begin/end of line or file
 shift CLIP: begin selection. Move the cursor to the selection end, type DEL to remove the selection (it will be copied to clipboard) or again shiftCLIP to copy selection to clipboard without removal. Type AC/ON to cancel selection.
 EXE: if a search/replace is currently active (F6 6) find next word occurence. Otherwise parse/execute.
 shift EXE: add a newline.
 DEL: remove selection or previous character if no selection active
 shift PASTE: copy clipboard
 ShiftINS (touche DEL): remove current line and copy to clipboard
 AC/ON: cancel selection or cancel search/replace or check syntax (like F6 1)
 EXIT: leave text editor to the commandline. Type EXIT again to come back to the text editor.
10 Remarks
On color models, you must first press MENU before shutting down the calculator with shift ON. When you press ON again, press MENU to go back in KhiCAS.
If you connect a color model to your PC as a USB disk, you will have to press a key after you have pressed F1, otherwise nothing happens.
The memory available for computations is about 500K with the color g3a addin on the CG50, and 58K on the monochrom g1a addin.
The light version in one file is not a full version of Xcas because the maximal size for a Casio addin is too small (2 Mo). The more complete version of $\chi$CAS (see next section) is distributed in 2 files, one of them is run from a section of the RAM of the FXCG50 that is currently not used by Casio.
11 More complete version for the CG50
11.1 MicroPython 1.12
You can switch the shell interpreter from shift SETUP. The menu background color of the shell reflects the active interpreter (yellow=MicroPython, magenta or cyan for Xcas native or Xcas Python compatible).
Available modules: turtle (more complete version, with filled objects), graphic (more complete than casioplot), matplotl, arit (integer arithmetic), linalg/numpy (linear algebra, matrices), ulab (scipy compatibility), cas (CAS from Python).
11.2 Geometry, 3d, CAS spreadsheet...
Xcas basic 2d and 3d geometry commands are available. One can plot
2 variables function or parametric plots, cones, solids, planes, ...
For example type F4 * 5 F2 EXE
to draw a cube or shift F4
1
to select the plot command, and enter x^2y^2
.
The 3d rendering engine is slow on the calculator, therefore the drawing precision is set to a low value by default (this impacts mostly objects with angles, like polyhedrons). You can modify this precision with F2 (faster, less precise) or F3 (slower, more precise).
Note that during the addin execution, the CPU speed is overclocked using code from Sébastien Michelland, similar to the Ptune3 addin.
If you just want one time a higher
precision rendering, type ^
and be patient. If you want to
interrupt this rendering, press DEL. Use the cursor keys to change the
viewpoint, 5 to reset to default viewpoint, and 
or +
to zoom in/out.
While a cursor key is
kept pressed, the precision is lower, when the key is released the
last position is redrawn with the default precision.
Type F4 to show/hide a second hidden objet, F5 to show/hide
intermediate points, F6 to show/hide polyhedron edges.
The file menu has an application item to access a formal spreadsheet, a finance app, a periodic table, ...
12 Copyright and Thanks to.
 Giac and $\chi$CAS, computing kernel (c) B. Parisse et R. De Graeve, 2022.
 $\chi$CAS interface adapted by B. Parisse from Eigenmath source code by Gabrial Maia and from Xcas source code.
 $\chi$CAS license GPL2. See details in
the
LICENSE.GPL2
file, inside khicasio.zip or GPL2 on the Free Software Foundation website. The source code of $\chi$CAS and of the required libraries libtommath and USTL are available in the Casio section of my webpage (see section 13).  Thanks to the active members of tiplanet and Planete Casio for answering questions and testing during the time I developed $\chi$CAS. Special thanks to LePhenixNoir (Prizm/35+eii help), Nemhardy (Prizm), and to critor for articles, tests and advertising. Thanks to all contributors of the Prizm programming portal. Thanks to Pavel Demin for compilation tricks that spared about 135K.
 Thanks to Camille Margot for her interest in this ports, and to Casio France for sending me calculators and an emulator license.
13 Developer infos.
Quick linux install : get
libmpfr.so.4
and copy it to /usr/local/lib
, check that /usr/local/lib
is in the paths listed in
/etc/ld.so.conf
and run sudo ldconfig
.
Now unarchive
casiolocal.tgz,
this is a working crossgcc for Casio calculators with additional
libraries (libc, ustl, tommath).
You will also need to install
mkg3a
to build addins for the FXCG.
Then get giac2.tgz
or
giacbf.tgz,
unarchive and run make
. For the light version get giac90.tgz
If something goes wrong, here are some details.
You must install the gcc crosscompiler
for sh3eb CPU, following this
tutorial (French).
I have configured gcc like this
../gcc5.3.0/configure target=sh3ebelf prefix="$HOME/opt/sh3ebelf" disablenls disableshared disablemultilib enablelanguages=c,c++ withoutheaders
Unfortunately, there is no support for sh3eb in the newlib
(C librairy) of gcc, nor for libstdc++
.
The libc is replaced by
libfxcg
(for CG50) (it comes from the original SDK with a few modifications,
corrections of small bugs, added missing functions like qsort, ...),
In the same
folder, you will also find tommath.tgz
(big integer
support) and ustl.tar.gz
(standard template library)
that I also had to modify to make it work with sh3ebelfg++,
with partial success, i.e. enough support to build Giac
(vector/string/map supported, I/O on files are not supported,
there is a custom iostream file for cin/cout minimal support).
Unarchive and compile with make.
For the monochrom Fx9860GIII, get
giac35.tar.bz2 and
run make
in the giac35/src0
directory.