What’s here.
A slew of programs and functions for the TI-89, TI-92, and TI-92 Plus calculators. Everything is organized into eight folders:

  1. calc (single variable calculus)
  2. mv (multivariable calculus and optimization)
  3. lin (linear algebra)
  4. de (differential equations)
  5. pr (probability)
  6. quad (Gaussian quadrature)
  7. sp (special functions)
  8. gnrl (general stuff)

Documentation
Each program contains a very brief description of how to use it and what it does. This can be seen by pressing Contents... (F6) in VAR-LINK. Unfortunately that only shows the first several lines, so in some cases you'll need to open the program/function in the program editor to see it all.

In the Contents section below, there are links to thorough pages of examples.

Downloading and Installation
The folders can be downloaded all at once as a zipped file. There are two versions: (1) old-fashioned TI-92 group files with .9Xg extensions, and (2) normal folders containing functions/programs with .89f/.89p extensions, which have a few minor changes for the TI-89's smaller screen. Here are the download links:

9Xgfiles.zip                     89fpfiles.zip          

Once you have the unzipped files on your computer, you need the TI Graph-Link cable and TI Connect Software to communicate with your calculator.

To install the .9Xg files, just drag them onto the window of the TI Device Explorer program after you've connected with your calculator. To install a folder containing .89p/.89f files, first open the folder and select all the files in it, and then drag them onto the Device Explorer window. The enclosing folder will be created automatically. (At least that works for me.)

Important: If you change the folder structure, you're going to have to do some modifications in many of the programs.

Disclaimer
These programs were not written to be particularly user friendly. In particular, there is little or no checking for bad user input. Also, many of the programs use other programs, so the folder structure needs to be left intact, unless you want to do some troubleshooting and modification.

Though effort has been made to ensure the accuracy of these programs, no guarantee of accuracy is stated nor implied. No one but yourself is responsible for anything that might happen as a result of using these programs. None of these programs should be used in mission-, life-, or grade-critical applications without extensive testing, for which you alone are responsible.


Links

TI Student Center

Ask a question of the TI-89/92 Discussion Group at TI

Ray Kremer’s ticalc.org


Brooks/Cole have made my TI-89/92 “CalcLabs” manual available as a free PDF. Enjoy.

Enjoy! Please report errors and send comments here:mail

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Contents

Single Variable Calculus

  • sgnchng
    searches for a sign change in the values of a function
  • secgraph
    plots the graph of a function along with a collection of secant lines
  • tangraph
    plots the graph of a function along with a collection of tangent lines
  • derlist
    computes a list of the first n derivatives of a function
  • newt
    finds a root of a function and displays a table of the iterates
  • newtfn
    root found by Newton's Method as a function of the initial guess
  • grphnewt
    creates a graphical display of the Newton's Method iteration
  • leftbox
    creates a graphical display of the left-endpoint approximation to the area under a curve
  • rightbox
    creates a graphical display of the right-endpoint approximation to the area under a curve
  • midbox
    creates a graphical display of the midpoint approximation to the area under a curve
  • trapez
    creates a graphical display of the trapezoidal approximation to the area under a curve
  • simpson
    computes the Simpson's Rule approximation to the integral of a function
  • wincheck
    a boring utility

Multivariable Calculus and Optimization

  • arrow
    plots an arrow to represent a vector in the plane
  • showvecs
    plots a collection of vectors in the plane
  • vpproj
    computes the projection of a point in 3D onto a “viewing plane”
  • view3d
    plots a 3d parametric curve (a “space curve”)
  • viewmore
    basically the same as view3D; used in
    parasurf
  • parasurf
    plots a 3D parametric surface
  • vecfield
    plots a 2D vector field (with arrowheads!)
  • grad
    computes the gradient of a function of any number of variables
  • div
    computes the divergence of a vector field of any number of variables
  • curl
    computes the curl of a 3D vector field
  • laplace
    computes the Laplacian of a function of any number of variables
  • hessian
    computes the hessian matrix (2nd derivative) of a function of any number of variables
  • evalgrad
    evaluates a vector function at a given point
  • evalhesn
    evaluates a matrix function at a given point
  • jacobian
    computes the Jacobian matrix of a vector field (or transformation from Rn to Rn)
  • newtstep
    computes one step of Newton's Method for finding a zero of a vector field (or transformation
    from Rn to Rn)
  • qapprox
    computes the quadratic approximation to a function of any number of variables at a given point
  • wincheck

Linear Algebra

  • lufac
    computes the LU factorization of a matrix
  • lusolve
    solves LUx = b
  • cholfac
    computes the Cholesky factorization LLT of a symmetric, positive definite matrix
  • cholsol
    solves Ax = b by means of the Cholesky factorization of A, if A is symmetric and positive definite
  • nullsp
    returns a description of the null space of a matrix
  • nullvecs
    returns a basis for the null space of a matrix
  • eignvals
    computes the eigenvalues of a matrix by the least efficient method possible
  • eignvec    Bug alert!
    computes the eigenvector(s) of a matrix corresponding to a particular eigenvalue
  • qrfac
    computes the QR factorization of a matrix
  • qform
    decodes the result of qrfac to display Q
  • qrsolve
    solves Ax = b by means of the QR factorization of A
  • gschmidt
    orthogonalizes the columns of a matrix

Differential Equations

  • slopefld
    plots the slope (direction) field of a differential equation (or pair of equations)
  • imeuf, imeug
    functions for using the Improved Euler's (a.k.a. Heun's) Method to plot approximate
    solutions of a pair of differential equations
  • rkstep2
    computes one step of 4th-order Runge-Kutta for a pair of differential equations
  • ndsolve2
    computes an array of points along an approximate solution of a pair of differential
    equations (uses rkstep2)
  • ndplot2
    plots an approximate solution of a pair of differential equations (uses ndsolve2)

Probability

  • bin, cbin
    binomial and cumulative binomial probabilities, resp.
  • poisson, cpoisson
    Poisson and cumulative Poisson probabilities, resp.
  • nrml
    cumulative probabilities from the standard normal distribution
  • nrmlpctl
    percentiles of the standard normal distribution (a great application of Newton's Method!)
  • zalpha
    critical z values associated with tail area
  • zcntrl
    critical z values associated with central area
  • tdist
    cumulative probabilities from Student's t-distribution with r degrees of freedom
  • tpctl
    percentiles of Student's t-distribution with r degrees of freedom
  • talpha
    critical t values associated with tail area in Student's t-distribution with r degrees of freedom
  • tcntrl
    critical t values associated with central area in Student's t-distribution with r degrees of freedom
  • chi2
    cumulative probabilities from the chi-square distribution with r degrees of freedom
  • chi2pctl
    percentiles of the chi-square distribution with r degrees of freedom

Gaussian Quadrature

  • gauss5
    five-point Gaussian quadrature
  • gauss7
    seven-point Gaussian quadrature
  • gauss11
    eleven-point Gaussian quadrature
  • cmpgauss
    composite Gaussian quadrature based on gauss11

A Few Special Functions

  • dblfac
    “double factorial” n(n-2)(n-4) ... (2 or 1)
  • gamma
    the Gamma function. Gamma(x) is defined for all reals except the negative integers.
    If n is a positive integer, then Gamma(n) = (n-1)!
  • expint1
    the “exponential integral” function
  • besselj
    the Bessel function Jn (“first kind”)
  • bessely
    the Bessel function Yn (“second kind”)

General

  • circles
    draws random circles on the screen
  • polygon
    plots a triangulated regular polygon
  • makelist
    computes an array of points (xk, f(xk)), k = 1, ..., n
  • nestlist
    computes an array of recursively defined points (xk+1,yk+1) = (f(xk,yk), g(xk,yk)), k = 1, .. n
  • listplot
    creates a piecewise linear graph from an array of points as returned by makelistor nestlist


 

This work is dedicated to the numerical analysts at NCSU who corrupted me in grad school.