Texas Instruments TI-89 User Manual - Page 817

Exec CATALOG Exec string [, expression1] [, expression2] ... Executes a string consisting of a series of Motorola 68000 op-codes. These codes act as a form of an assembly-language program. If needed, the optional expressions let you pass one or more arguments to the program. For more information, check the TI Web site: http://www.ti.com/calc Warning: Exec gives you access to the full power of the microprocessor. Please be aware that you can easily make a mistake that locks up the calculator and causes you to lose your data. We suggest you make a backup of the calculator contents before attempting to use the Exec command. Exit CATALOG Exit Exits the current For, While, or Loop block. Exit is not allowed outside the three looping structures (For, While, or Loop). Program listing: :0! temp :For i,1,100,1 : temp+i! temp : If temp>20 : Exit :EndFor :Disp temp Contents of temp after execution: 21 exp4list() CATALOG exp4list(expression,var) ⇒ list Examines expression for equations that are separated by the word "or," and returns a list containing the right-hand sides of the equations of the form var=expression. This gives you an easy way to extract some solution values embedded in the results of the solve(), cSolve(), fMin(), and fMax() functions. solve(x^2ì xì 2=0,x) ¸ x=2 or x=ë 1 exp4list(solve(x^2ì xì 2=0,x),x) ¸ {ë 1 2} Note: exp4list() is not necessary with the zeros and cZeros() functions because they return a list of solution values directly. expand( ) MATH/Algebra menu expand(expression1 [, var]) ⇒ expression expand(list1 [,var]) ⇒ list expand(matrix1 [,var]) ⇒ matrix expand(expression1) returns expression1 expanded with respect to all its variables. The expansion is polynomial expansion for polynomials and partial fraction expansion for rational expressions. expand((x+y+1)^2) ¸ xñ + 2ø xø y + 2ø x + yñ + 2ø y + 1 expand((x^2ì x+y^2ì y)/(x^2ù y^2ì x^2ù yì xù y^2+xù y)) ¸ The goal of expand() is to transform expression1 into a sum and/or difference of simple terms. In contrast, the goal of factor() is to transform expression1 into a product and/or quotient of simple factors. Appendix A: Functions and Instructions 817