HP 33s Scientific manual Interrupting a Solve Calculation, Choosing Initial Guesses for Solve

Interrupting a SOLVE Calculation

To halt a calculation, press ‡or g. The current best estimate of the root is in the unknown variable; use Što 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= v0 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.

Solving Equations 7–7