Texas Instruments TI-83 PLUS - Manual (Page 81)

TI-83 Plus Math, Angle, and Test Operations 78
Controlling the Solution for Solver or solve(
The TI-83 Plus solves equations through an iterative process. To control
that process, enter bounds that are relatively close to the solution and
enter an initial guess within those bounds. This will help to find a solution
more quickly. Also, it will define which solution you want for equations
with multiple solutions.
Using solve( on the Home Screen or from a Program
The function solve( is available only from
CATALOG
or from within a
program. It returns a solution (root) of expression for variable , given an
initial guess , and lower and upper bounds within which the solution is
sought. The default for lower is L 1 â 99. The default for upper is 1 â 99. solve(
is valid only for real numbers.
solve( expression , variable , guess [ ,{ lower , upper } ] )
expression is assumed equal to zero. The value of variable will not be
updated in memory. guess may be a value or a list of two values. Values
must be stored for every variable in expression , except variable , before
expression is evaluated. lower and upper must be entered in list format.