I am trying to learn how to solve a quartic equation. In page http://en.wikipedia.org/wiki/Quartic_function I found the "Summary of Ferrari's method" part looks easier for me but still have two difficulties: 1. Do you think I can solve a general quartic equation by only following this part and ignoring all the other parts? 2. What is the signs for: "positive negative s" and "positive negative t".
On Jul 31, 12:44 pm, Wood <wood0...@sohu.com> wrote:
> I am trying to learn how to solve a quartic equation. In > page http://en.wikipedia.org/wiki/Quartic_function > I found the "Summary of Ferrari's method" part looks easier > for me but still have two difficulties: > 1. Do you think I can solve a general quartic equation > by only following this part and ignoring all the other parts?
I think so - why not try it, and see?
> 2. What is the signs for: "positive negative s" and > "positive negative t".
When you see plus-or-minus with a subscript s, it means it doesn't matter whether you choose the plus sign or the minus sign, but whichever choice you make, you have to make that same choice whenever you see plus-or-minus with a subscript s. Likewise for t, where you can make either choice, no matter which choice you made for s. -- GM
Thanks a lot! I really want to have a try, but don't know how to deal with the plus-minus-s......is this possible...I mean possible....give me a numerical example following the "Summary of Ferrari's method"?
On Jul 30, 10:20 pm, Wood <wood0...@sohu.com> wrote:
> Thanks a lot! > I really want to have a try, but don't know how to deal with the plus-minus-s......is this possible...I mean possible....give me a numerical example following the "Summary of Ferrari's method"?
You get two solutions: one by choosing the '+' sign and another by choosing the '-' sign. The Wiki article makes this clear.
> Thanks a lot! > I really want to have a try, but don't know how to deal with the > plus-minus-s......is this possible...I mean possible....give me a > numerical example following the "Summary of Ferrari's method"?
Why don't you try to do that and then, if you find an obstacle, you tell us what that obstacle was?
Besides, when you find a plus/minus sign with subscript _s_, always choose + or always choose -. If you find a minus/plus sign with subscript _s_ do the opposite choice. The same thing applies to the _t_ subscript.
|
