Texas Instruments PLUS TI-89 - Manual (Page 463)

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(2xù y)+ ‡(2xù y) ¸
ln(2ø xø y) + ‡(2ø xø y)
expand(ans(1)) ¸
ln(xø y) + ‡2ø ‡(xø y) + ln(2)
expand(ans(1))|y>=0 ¸
ln(x) + ‡2ø ‡xø ‡y + ln(y) + ln(2)
sign(xù y)+abs(xù y)+ e^(2x+y)
¸
e 2ø x+y + sign(xø y) + |xø y|
expand(ans(1)) ¸
sign(x)øsign(y) + |x|ø|y|+ (e x ) 2 øe y
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)") ¸
xс + 2ш x + 1
"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 ...}
{1,2,2,2,3,4,5,7}! L2 ¸
{1 2 ...}
ExpReg L1,L2 ¸ Done
ShowStat ¸
¸
Regeq(x) "y1(x) ¸ Done
NewPlot 1,1,L1,L2 ¸ Done
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