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![[parent]](http://images.planetmath.org:8080/images/uparrow.png) Viewing Message
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| ``undefined roots of a cubic?''
by abeckwith on 2004-05-14 14:34:32 |
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| Hello, PlanetMath.
I am a high school math teacher and designed a special project for my students that used the formula I found on your website for solutions to cubic equations. I also wrote a program to check their answers for a variety of coefficients, a, b, and c.
One student was assigned coefficients -3, 3, and 1. When she did her calculations, she ended up with an expression that involved dividing by 0, implying that the answer was undefined. I checked her calculations on my calculator program and discovered same. We looked at the graph of the cubic equation and found that it should have 1 real and 2 complex solutions. I also found that -3, 3, with any other value for the last constant would give a denom of 0.
My question is this: is there some restriction on the constants in the use of the formula that one should be aware of when using it? The page that has the formula mentions none.
Since this is a problem that has been solved completely, it would seem that the formula should produce answers for any values of the three constants.
Thank You. |
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