Math Is Fun Forum

CIV

Member

Registered: 2014-11-09

Posts: 74

How do I solve this polynomial?

I don't know why the book has me doing this.... I wasn't taught how to solve something like this yet. This is actually part of a calc 1 problem. Im graphing functions. It's part of the numerator for the second derivative. There's actually a 2 that I factored out, but it shouldn't be need to solve this. Well, technically now that I read the book it wants me to use a graphing calculator to find the important points. This polynomial is whats need to calculate possible inflection points.

I tried rational roots and it provided me with nothing that works, lol.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,140

Re: How do I solve this polynomial?

hi CIV

By graphing I'm getting a single value of approximately x = 4.4

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: How do I solve this polynomial?

There is one real root at

Of course, you now have to deflate that out and solve a quadratic, it will yield two complex roots.

I don't know why the book has me doing this.... I wasn't taught how to solve something like this yet.

Oh boy! I feel a rant coming on...

[Begin rant]

There is a good reason them there books give the uninitiated problems like this. It is because the authors of them there books, mathematicians all, think this is a trivial problem. Just go get your calculator and whamo! It is all done. Well the fact is hundreds if not thousands of books have been written on locating and getting the roots of polynomials like that one. They are so important that even I, a bumpkin, has read some of them. Do they not say that they know everything about polynomials? Do they not say that computation is trivial? Do not believe it.

[End Rant]

By the way to EVW, I did not need Wolfram or Mathematica to get this. A TI-85 is enough. In my younger days a pencil and paper and some soda would have been enough. Bet you and maybe the Colonel ain't got it yet...

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

ElainaVW

Member

Registered: 2013-04-29

Posts: 580

Re: How do I solve this polynomial?

Mr m:

You're half right I can't get that answer but Eric did it in less than 5 min. He said to tell you that as long as he is around you're second best. Can you make it to Canaveral this weekend?

CIV

Member

Registered: 2014-11-09

Posts: 74

Re: How do I solve this polynomial?

Yea ibgot 4.4ish using the graphing calc as well, but i was kind of dead set on solving it:( Im going to have to get some of the books bobbym is talking about. Evenetually. I am one who likes to know how things work. Im not satisfied unless i do.