Texas Instruments TI-89, TI-92

446 Appendix A: Functions and Instructions

8992APPA.DOC TI-89 / TI-92 Plus: Appendix A (US English) Susan Gullord Revised: 02/23/01 1:48 PM Printed: 02/23/01 2:21 PM Page 446 of 132

expand(expression1,[var]) also distributes

logarithms and fractional powers regardless

of var. For increased distribution of

logarithms and fractional powers, inequality

constraints might be necessary to guarantee

that some factors are nonnegative.

expand(expression1, [var]) also distributes

absolute values, sign(), and exponentials,

regardless of var.

Note: See also tExpand() for trigonometric

angle-sum and multiple-angle expansion.

ln(2xùy)+‡(2xùy) ¸

ln(2øxøy) +

‡

(2øxøy)

expand(ans(1)) ¸

ln(xøy) +

‡

2ø

‡

(xøy) + ln(2)

expand(ans(1))|y>=0 ¸

ln(x) +

‡

2ø

‡

xø

‡

y + ln(y) + ln(2)

sign(xùy)+abs(xùy)+ e^(2x+y)

e2øx+y + sign(xøy) + |xøy|

expand(ans(1)) ¸

sign(x)øsign(y) + |x|ø|y|+ (ex)2øey

expr() MATH/String menu

expr(string) ⇒ expression

Returns the character string contained in

string as an expression and immediately

executes it.

expr("1+2+x^2+x") ¸xñ+ x + 3

expr("expand((1+x)^2)") ¸

+ 2øx +

"Define cube(x)=x^3"!funcstr

"Define cube(x)=x^3"

expr(funcstr) ¸Done

cube(2) ¸8

ExpReg MATH/Statistics/Regressions menu

ExpReg list1, list2 [, [list3] [, list4, list5]]

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.

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.

In function graphing mode:

{1,2,3,4,5,6,7,8}!L1 ¸

{1 2 ...}

,2,2,2,3,4,5,7

}

!L2

{1 2 ...}

ExpReg L

,L2

Done

owStat

Regeq(x)"y1(x) ¸Done

NewP

,L2

Done

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