Texas Instruments PLUS TI-89 - Manual (Page 350)

Chapter 19: Numeric Solver 333
19SOLVER.DOC TI-89/TI-92 Plus: Numeric Solver (English) Susan Gullord Revised: 02/23/01 1:16 PM Printed: 02/23/01 2:19 PM Page 333 of 10
Chapter 19:
Numeric Solver
Preview of the Numeric Solver ............................................................ 334
Displaying the Solver and Entering an Equation ............................... 335
Defining the Known Variables .............................................................. 337
Solving for the Unknown Variable ....................................................... 339
Graphing the Solution............................................................................ 340
The Numeric Solver lets you enter an expression or equation,
define values for all but one unknown variable, and then solve for
the unknown variable.
You can also graph the solution.
As in the example above, the Numeric Solver is often used to
solve closed-form equations. But it also gives you a quick way to
solve equations such as transcendental equations in which there
is no closed form.
For example, you could rearrange the following equation
manually to solve for any of the variables.
a = (m2 ì m1) / (m2 + m1) ù g m1 = (g ì a) / (g + a) ù m2
With an equation such as the following, however, it may not be as
easy to solve for
x manually.
y = x + e x
The Numeric Solver is
particularly useful for such
equations.
19
Note: To solve for the
unknown variable from the
Home screen or a program,
use nSolve() as described
in Appendix A.
After entering an equation
and its known values,
place the cursor on the
unknown variable and
press
„ .
The x axis is the unknown
variable. The y axis is the
left–rt value, which gives
the solution’s accuracy.
The solution is precise
where the curve crosses
the x axis.