Texas Instruments TI-89, TI-92

422 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 422 of 132

comDenom(expression1,var) returns a reduced

ratio of numerator and denominator expanded

with respect to var. The terms and their factors

are sorted with var as the main variable.

Similar powers of var are collected. There

might be some incidental factoring of the

collected coefficients. Compared to omitting

var, this often saves time, memory, and screen

space, while making the expression more

comprehensible. It also makes subsequent

operations on the result faster and less likely to

exhaust memory.

comDenom((y^2+y)/(x+1)

^2+y^2+y,x) ¸

comDenom((y^2+y)/(x+1)

^2+y^2+y,y) ¸

If var does not occur in expression1,

comDenom(expression1,var) returns a reduced

ratio of an unexpanded numerator over an

unexpanded denominator. Such results usually

save even more time, memory, and screen

space. Such partially factored results also

make subsequent operations on the result

much faster and much less likely to exhaust

memory.

comDenom(exprn,abc)!comden

(exprn) ¸Done

comden((y^2+y)/(x+1)^2+y^2+y)

Even when there is no denominator, the

comden function is often a fast way to achieve

partial factorization if factor() is too slow or if it

exhausts memory.

Hint: Enter this comden() function definition

and routinely try it as an alternative to

comDenom() and factor().

comden(1234x^2ù(y^3ìy)+2468x

ù(y^2ì1)) ¸

1234øxø(xøy + 2)ø(yñì1)

conj() MATH/Complex menu

conj(expression1) ⇒ expression

conj(list1) ⇒ list

conj(matrix1) ⇒ matrix

Returns the complex conjugate of the

argument.

Note: All undefined variables are treated as

real variables.

conj(1+2i) ¸1 ì2øi

conj([2,1ì3i;ëi,ë7]) ¸







2 1+3øi

i ë7

conj(z) z

conj(x+iy) x + ëiøy

CopyVar CATALOG

CopyVar var1, var2

Copies the contents of variable var1 to var2.

If var2 does not exist, CopyVar creates it.

Note: CopyVar is similar to the store

instruction (!) when you are copying an

expression, list, matrix, or character string

except that no simplification takes place

when using CopyVar. You must use CopyVar

with non-algebraic variable types such as Pic

and GDB variables.

x+y!a ¸x + y

0!x

¸1

CopyVar a,

Done

a!c

y +

Var x

Done

x + y

y +