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: calc (single variable calculus) mv (multivariable calculus and optimization) lin (linear algebra) de (differential equations) pr (probability) quad (Gaussian quadrature) sp (special functions) 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. New!   An Interactive Book

Enjoy! Please report errors and send comments here: You are visitor number since 3.29.99. (Counter courtesy of WebCounter) 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 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

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