• May 21st 2008, 06:36 AM
Gilbert
Hi,

Can someone help me on a website for the classification of quadrics(ellipsoids

parabolois,............)starting from the general second order equation.

Thanks.
• May 21st 2008, 03:16 PM

If that is it, just search for "quadratics."

What do you mean by "classifying"?

Any book explaining basic analytic geometry will tell you enough.

Look for "completing the square" if you want more.

Look for "polynomials of degree two" or "second degree polynomials" for more.

Bye.
• May 21st 2008, 06:20 PM
Reckoner
Quote:

Originally Posted by Gilbert
Hi,

Can someone help me on a website for the classification of quadrics(ellipsoids

parabolois,............)starting from the general second order equation.

Thanks.

Hi, Gilbert. The Wikipedia article on quadrics and MathWorld's Quadratic Surfaces article has a list of the different types of quadric surfaces, and a simple Google search for "Quadrics" will turn up more.

For classification, you may need to perform a rotation of axes to eliminate the $\displaystyle xy,\;xz,\;\text{or}\;yz$ terms in its equation. Once in a normalized form, classification should be straightforward.
• May 21st 2008, 08:12 PM
Thanks.

That's beyond my experience although I have seen it, I have never to date had access to Mathematica or similar software nor the funds to purchase it.

A former calculus teacher once told me that he wanted to teach a class in Mathematica, stating, "You'll never get anywhere in mathematics without a computer." I am not so sure of what he meant by that, but I don't know if I will ever have enough discretionary cash to purchase this kind of software.

Quadratic Surface -- from Wolfram MathWorld

I wonder if a student edition of Mathematica is available and affordable.

It would be useful for help my daughter with math education.
• May 21st 2008, 11:13 PM
earboth
Quote:

... I am not so sure of what he meant by that, but I don't know if I will ever have enough discretionary cash to purchase this kind of software.
...

It would be useful for help my daughter with math education.

You'll find here a mathematical toolbox (including 3-D-graphs of functions and relations):

EuMathT - Euler Math Toolbox

I don't use this program so I can't help you very much how it is used etc. But if I remember correctly CaptainBlack is somehow involved in this project.

Give it a try.

Edit: To complete your collection of useful math programs:

Graph

That's the software used at this forum to draw graphs of functions

GeoGebra

This program is quite useful if you want to do some geometric constructions.

Certainely it isn't necessary to point out, that all computer programs are tools and you must know the math before you can use such a program appropriately.
• May 22nd 2008, 06:58 AM
Gilbert
Hi,