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HP's calculator website has 4 learning modules about using the SOLVE feature. I encourage you to look at them and download them.

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Hi Eric,

I think the following posts should be helpful for understanding how to get the 33s solver to work most effectively. Also be sure to read the manual and the guides on the hp website--the solver is a powerful tool, but slightly different from the 32sii in some ways (though just as good if not better) and it is helpful to understand the nuances.

http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv014.cgi?read=62608

http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv014.cgi?read=61213

http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv014.cgi?read=61224

http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv014.cgi?read=61136

Best regards,

Bill

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Quote:

After entering the quadratic form a*sq(x) + b*x = - c
I am concerned to obtain only one root (and incorrect).

As Namir and Bill said, there is osme supplemental info available at HP's website. The info describes how the 33S will use a "direct solution" method for equations of certain forms, solving algebraically instead of iteratively. This is not always desirable, because one must then know how to modify the equaiton so that the 33S will find the other roots.

In any case, it should have returned at least one correct answer. What were the coefficients?

-- KS

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Don't forget that computer programs are not magical black boxes. They are based on algorithms, and all HP SOLVE programs are based on well known mathematical algorithms, such as Newton's, regula falsi, etc., which DO have limitations, i.e., they are not always applicable, they will not always converge to a root; that depends on some conditions the function must fulfill. Even the most powerful computer in the world programmed with the "best" root-finding algorithm can fail to return a correct answer in some cases, and that doesn't mean its programmers are incompetent or that the programs contain bugs. Get used to it.