Texas Instruments TI-89, TI-92

Chapter 3: Symbolic Manipulation 73

03SYMBOL.DOC TI-89/TI-92 Plus: Symbolic Manipulation (English) Susan Gullord Revised: 02/23/01 10:52 AM Printed: 02/23/01 2:12 PM Page 73 of 24

Use the solve ( „ 1) function to solve an equation for a specified

variable.

solve(equation, var)

Solve x + y ì5 = 2x ì5y

for x.

Notice that solve displays

only the final result.

To see intermediate results, you can manually solve the equation

step-by-step.

Consider a set of two equations with

two unknowns:

2x ì3y = 4

ëx + 7y = ë12

To solve this system of equations, use any of the following methods.

Method Example

Use the solve function

for a one-step solution.

solve(2xì3y=4 and ëx+7y=ë12,{x,y})

Use the solve function

with substitution ( | )

for step-by-step

manipulation.

Refer to the preview at the beginning of

this chapter, which solved for x = ë8/11

and y = ë20/11.

Use the simult function

with a matrix.

Enter the coefficients as a matrix and the

results as a constant column matrix.

Use the rref function

with a matrix.

Enter the coefficients as an augmented

matrix.

Solving an Equation

Note: An operation such as

| 2 Ù

subtracts 2x from

both sides.

Solving a System of

Linear Equations

Note: The

simult

and

rref

matrix functions are not on

the

„ Algebra

menu. Use

the

Catalog.

| 2 x

| y

p · 1

« 5

x « y | 5 Á 2x | 5y