Texas Instruments TI-89 User Manual - Page 819

ExpReg MATH/Statistics/Regressions menu ExpReg list1, list2 [, [list3] [, list4, list5]] In function graphing mode: Calculates the exponential regression and updates all the system statistics variables. All the lists must have equal dimensions except for list5. list1 represents xlist. list2 represents ylist. list3 represents frequency. list4 represents category codes. list5 represents category include list. {1,2,3,4,5,6,7,8}! L1 ¸ {1,2,2,2,3,4,5,7}! L2 ¸ ExpReg L1,L2 ¸ ShowStat ¸ Note: list1 through list4 must be a variable name or c1-c99 (columns in the last data variable shown in the Data/Matrix Editor). list5 does not have to be a variable name and cannot be c1-c99 . ¸ Regeq(x)"y1(x) ¸ NewPlot 1,1,L1,L2 ¸ ¥% {1 2 ...} {1 2 ...} Done Done Done factor( ) MATH/Algebra menu factor(expression1[, var]) ⇒ expression factor(list1[,var]) ⇒ list factor(matrix1[,var]) ⇒ matrix factor(expression1) returns expression1 factored with respect to all of its variables over a common denominator. expression1 is factored as much as possible toward linear rational factors without introducing new non-real subexpressions. This alternative is appropriate if you want factorization with respect to more than one variable. factor(a^3ù x^2ì aù x^2ì a^3+a) ¸ aø(a ì1)ø(a + 1)ø(x ì1)ø(x + 1) factor(x^2+1) ¸ xñ + 1 factor(x^2ì 4) ¸ (x ì 2)ø (x + 2) factor(x^2ì 3) ¸ xñ ì 3 factor(x^2ì a) ¸ xñ ì a factor(expression1,var) returns expression1 factored with respect to variable var. expression1 is factored as much as possible toward real factors that are linear in var, even if it introduces irrational constants or subexpressions that are irrational in other variables. The factors and their terms are sorted with var as the main variable. Similar powers of var are collected in each factor. Include var if factorization is needed with respect to only that variable and you are willing to accept irrational expressions in any other variables to increase factorization with respect to var. There might be some incidental factoring with respect to other variables. factor(a^3ù x^2ì aù x^2ì a^3+a,x) ¸ aø (añ ì 1)ø (x ì 1)ø (x + 1) factor(x^2ì 3,x) ¸ (x + ‡3)ø (x ì ‡3) factor(x^2ì a,x) ¸ (x + ‡a)ø (x ì ‡a) Appendix A: Functions and Instructions 819