HP 33s - Manual (Page 117)

Solving Equations 7–7
Interrupting a SOLVE Calculation
To halt a calculation, press ‡ or g . The current best estimate of the root is in
the unknown variable; use | Š to view it without disturbing the stack.
Choosing Initial Guesses for SOLVE
The two initial guesses come from:
„ The number currently stored in the unknown variable.
„ The number in the X–register (the display).
These sources are used for guesses whether you enter guesses or not. If you enter
only one guess and store it in the variable, the second guess will be the same value
since the display also holds the number you just stored in the variable. (If such is
the case, the calculator changes one guess slightly so that it has two different
guesses.)
Entering your own guesses has the following advantages:
„ By narrowing the range of search, guesses can reduce the time to find a
solution.
„ If there is more than one mathematical solution, guesses can direct the SOLVE
procedure to the desired answer or range of answers. For example, the
equation of linear motion
d = v
0
t +
1
/
2
gt
2
can have two solutions for t. You can direct the answer to the required
solution by entering appropriate guesses.
The example using this equation earlier in this chapter didn't require you to
enter guesses before solving for T because in the first part of that example
you stored a value for T and solved for D. The value that was left in T was a
good (realistic) one, so it was used as a guess when solving for T.