Factoring f(x)=x^3+x to Find x-Axis Intersection

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    Factoring Intersection
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Discussion Overview

The discussion revolves around the function f(x)=x^3+x and the participants' attempts to factor it in order to demonstrate that the graph intersects the x-axis only once. The focus is on the mathematical reasoning behind the factorization and the implications for finding x-intercepts.

Discussion Character

  • Mathematical reasoning
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant initially factors the function to x(x^2+1) but expresses uncertainty about its usefulness.
  • Another participant affirms the factorization and prompts a discussion about the properties of x-intercepts.
  • It is noted that the equation x(x^2+1)=0 can be used to find x-intercepts, with the x factor yielding a real zero at x=0.
  • Discussion highlights that the factor x^2+1 has no real zeros, indicating that it does not contribute to x-axis intersections.
  • A participant expresses satisfaction with the clarification provided in the discussion.

Areas of Agreement / Disagreement

Participants generally agree on the factorization of the function and the conclusion that there is only one real x-intercept at x=0. However, the implications of the complex roots from the factor x^2+1 are acknowledged but not fully resolved in terms of their relevance to the graph.

Contextual Notes

The discussion does not resolve the implications of complex roots in the context of graphing in a two-dimensional Cartesian plane, nor does it fully explore the conditions under which the factorization is applied.

Who May Find This Useful

Students or individuals interested in polynomial functions, graphing, and the properties of x-intercepts may find this discussion beneficial.

david18
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Ive got a function of f(x)=x^3+x and I need to use factors to show that the graph crosses the x-axis once only.

I just factorised it to x(x^2+1) which isn't very helpful, and if i divide everything by x and complete the square with x^2+1 i get a negative number and stuff...

any help?
 
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david18 said:
Ive got a function of f(x)=x^3+x and I need to use factors to show that the graph crosses the x-axis once only.

I just factorised it to x(x^2+1) which isn't very helpful,
Oh yes it is!

So, you have found that f(x)=x(x^2+1)

What property, i.e, which equation must an x-intercept of the graph fulfill?
 
x(x^2+1)=0
 
david18 said:
Ive got a function of f(x)=x^3+x and I need to use factors to show that the graph crosses the x-axis once only.

I just factorised it to x(x^2+1) which isn't very helpful, and if i divide everything by x and complete the square with x^2+1 i get a negative number and stuff...

any help?

Good is that you factored the function. the x^2 + 1 factor has no "real" zeros; but the x factor has one real zero, being 0. (zero).

Let me try again in case this helps.
(x^2 + 1) = 0 for what real values of x? For NONE. We do not usually graph complex zeros in two dimensional cartesian plane (at least for our purposes here).

When is x=0 (using the other factor)? when x=0, already shown.
 
hi, thanks for the reply, it all makes sense now :)
 

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