Solving Polynomial: How to Expand Square Root

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Discussion Overview

The discussion revolves around the simplification of the expression \(\sqrt{x^3} + \sqrt{1+x^3}\). Participants explore methods to manipulate or expand the square roots involved, with a focus on achieving a single term in \(x\). The conversation includes elements of mathematical reasoning and clarification of definitions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant seeks assistance in simplifying the expression \(\sqrt{x^3} + \sqrt{1+x^3}\) to have only one term of \(x\).
  • Another participant questions whether the intention is to solve an equation or simplify the expression, suggesting that the latter is more likely.
  • A participant expresses uncertainty about how to approach the simplification, mentioning an incorrect attempt to combine the square roots.
  • One participant notes that Mathematica cannot simplify the expression further.
  • Another participant agrees that the expression is in its simplest form, while another points out that it does not qualify as a polynomial.
  • A participant provides a definition of a polynomial, emphasizing that the expression does not fit this definition due to the presence of square roots.
  • One participant suggests alternative manipulations of the expression but does not consider them simpler.
  • A later reply admonishes another for perceived spamming of the thread.

Areas of Agreement / Disagreement

Participants generally agree that the expression cannot be simplified into a polynomial form and that it remains in its simplest state. However, there is disagreement regarding the methods to manipulate or expand the expression, with no consensus on a preferred approach.

Contextual Notes

There is a lack of clarity regarding the assumptions behind the simplification attempts, and the discussion does not resolve the mathematical steps involved in manipulating the square roots.

jessawells
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hi,

can anyone show me how to solve this:

[tex]\sqrt{x^3} + \sqrt{1+x^3}[/tex]

i want to get it to so that there's only 1 term of x. but i don't know how to expand the squared root. any help is appreciated.
 
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Usually when you say solve an equation, you mean something like solve x + 1 = 2.

Did you mean solve :[tex]\sqrt{x^3} = \sqrt{1+x^3}[/tex] (Probably not, since this is a false statement)

or simplify

[tex]\sqrt{x^3} + \sqrt{1+x^3}[/tex]
?

I'm guessing the second one. Do you have an idea of how to approach it?
 
Last edited by a moderator:
hi,

yes, its the second case - simplifying the expression. I'm not sure at all how to approach it. I've thought about using the fact that both terms are squared - eg. making it [tex]\sqrt{x^3 + (1+x^3)}[/tex] but i know that's wrong. other than that, I've been trying to expand the [tex]\sqrt{1+x^3}[/tex] term, the way you would expand something like [tex](1+x)^2[/tex], but I've had no success. any help would be great.
 
Well Mathematica can't simplify it.
 
Agreed. That polynomial is in simplest form.
 
it's not a polynomial, either.
 
Thank you for giving us the correct definition of a polynomial.
 
Last edited by a moderator:
No... polynomials only have natural powers. A polynomial is something of the form

[tex]\alpha_0 + \alpha_1x + \alpha_2x^2 + \ . \ . \ . \ + \alpha_nx^n.[/tex]

which [itex]\sqrt{x^3} + \sqrt{x^3+1}[/itex] certainly is not.

Now, you can certainly do some interesting things to [itex]\sqrt{x^3} + \sqrt{x^3 + 1}[/itex], as usual. For example,

[tex]\sqrt{x^3} + \sqrt{x^3 + 1} = \frac{1}{\sqrt{x^3+1}-\sqrt{x^3}}[/tex]

[tex]= \sqrt{2\sqrt{x^3}\left(\sqrt{x^3}+\sqrt{1+x^3}\right) + 1}[/tex]

but I would by no means consider those simpler.
 
Please don't spam. You already posted your homework question here.
 

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