Texas Instruments PLUS TI-89 - Manual (Page 90)

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 ì 5 = 2x ì 5y
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 ì 3y = 4
ë x + 7y = ë 12
To solve this system of equations, use any of the following methods.
Method Example
Use the solve function
for a one-step solution.
solve ( 2x ì 3y=4 and ë x+7y= ë 12,{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 = ë 8/11
and y = ë 20/11 .
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
2 I 4 or the Catalog.
| 2 x
| y
p · 1
« 5
x « y | 5 Á 2x | 5y