The solver menu, Solving for the unknown variable – Texas Instruments TI-86 User Manual

Page 218

206

Chapter 15: Equation Solving

15EQSOLV.DOC TI-86, Chap 15, US English Bob Fedorisko Revised: 02/13/01 2:34 PM Printed: 02/13/01 3:04 PM Page 206 of 12

The Solver Menu

- t equation b

GRAPH

WIND

ZOOM

TRACE SOLVE

graphs the

solver zoom

solves for the unknown variable or

equation in eqn

displays the interactive-solver editor

window graphs eqn and
editor activates the trace cursor

To display the window editor, select

WIND

from the solver menu.

When you select

GRAPH

WIND

from the solver menu,

EDIT

replaces the item you selected on

the menu. To return to the interactive-solver editor from the graph or window editor, select

EDIT

Solving for the Unknown Variable

After you have stored all known variable values, set the bounds, and entered a guess
(optional), move the cursor to the prompt for the unknown variable.

To solve, select

SOLVE

from the solver menu (*).

♦

A small square marks the variable for which you
solved. The solution value is displayed.

♦

A small square also marks the

left

rt=

prompt. The

value at this prompt is the value of the left side of the
equation minus the value of the right side of the
equation, evaluated at the new value of the variable
for which you solved. If the solution is precise,

left

rt=0

is displayed.

Some equations have more than one solution. To look for additional solutions, you can
enter a new guess or set new bounds, and then solve for the same variable.

You can display other menus
in the interactive-solver editor

An ellipsis (...) indicates that
the variable value continues
beyond the screen. To scroll
the value, press

and

The squares disappear when
you edit any value.

After solving, you can edit a
variable value or edit the
equation, and then solve for
the same variable or another
variable in the equation.