|Re: HP 33S instructions|
Message #21 Posted by Gene on 14 Mar 2006, 11:51 a.m.,
in response to message #4 by Antonio Maschio (Italy)
These are not new revelations but have been documented even here on the forum.
I also do not believe they are "bugs", but behavior chosen for a purpose.
It works like this:
When an equation has one occurrence of a variable, and only one occurence, the 33S solver will use the direct solver to estimate a root. That is why the X^2-4=0 finds the solution x=2 and only x=2. It does not use an input value as a guess in this instance, since it uses the direct solver.
An equation such as X^2-5x-6 will use input guesses and find more than one root, since X occurs more than once in the equation.
To force the 33S to solve X^2-4=0 and find multiple roots, you must enter the equation as something like this:
This will use input guesses and find more than one root.
This is documented in the 33s learning modules available on HP's site.
You will have no luck claiming this is a bug to HP because this behavior was chosen and is considered the "way it is supposed to work".
So, to get around this behavior, if you have an equation with only one variable that is taken to a power, enter an extra term including 0 multiplied by the variable.
We might disagree with whether this should be the way it ought to operate, but that's the hand of cards we've been dealt.
If you haven't looked over the learning modules on HP's webpage for the 33S, you can find them here:
which will download all the modules in one zip file.
The two specific 33s modules dealing with the solver (which were written by Wlodek!) can be found here:
The second module (33sSolver2.pdf) has a discussion of the "Direct Solve" "feature".
Hope these help!