Decompossing a polynomial (keep getting the wrong result )

  • Thread starter Susanne217
  • Start date
  • Tags
    Polynomial
In summary, the conversation discussed decomposing a polynomial and finding the correct result. The polynomial f(x) = -x^2 - x + 1 was decomposed into linear terms, with the roots being determined as \frac{-1\pm\sqrt{5}}{2}. The correct solution was found to be f(x)=-\left[x-\left(\frac{-1+\sqrt{5}}{2}\right)\right]\left[x-\left(\frac{-1-\sqrt{5}}{2}\right)\right], with a factor of -1 being previously forgotten.
  • #1
Susanne217
317
0
decompossing a polynomial (keep getting the wrong result :()

Homework Statement



Given the polynomial f(x) = -x^2 - x + 1, decompose the polynomial into linear terms


The Attempt at a Solution



I get [tex](x-(-(\frac{-\sqrt{5}+1}{2}))((x-(-\frac{-\sqrt{5}-1}{2}))[/tex]

I seem to be missing a integer factor but can't get it to fit properly. Maybe one of you guys can point out my error ? Or where I doing this wrong :)
 
Physics news on Phys.org
  • #2


Well, the roots of your polynomial are [tex]\frac{-1\pm\sqrt{5}}{2}[/tex], so shouldn't you have

[tex]f(x)=-\left[x-\left(\frac{-1+\sqrt{5}}{2}\right)\right]\left[x-\left(\frac{-1-\sqrt{5}}{2}\right)\right][/tex]

?
 
  • #3


gabbagabbahey said:
Well, the roots of your polynomial are [tex]\frac{-1\pm\sqrt{5}}{2}[/tex], so shouldn't you have

[tex]f(x)=-\left[x-\left(\frac{-1+\sqrt{5}}{2}\right)\right]\left[x-\left(\frac{-1-\sqrt{5}}{2}\right)\right][/tex]

?


forgot the minus 1 I can see. Must be tired. Thanks :)
 

FAQ: Decompossing a polynomial (keep getting the wrong result )

What is the definition of decomposing a polynomial?

Decomposing a polynomial means breaking it down into simpler terms. This involves factoring out common factors and writing the polynomial as a product of simpler polynomials.

Why do I keep getting the wrong result when decomposing a polynomial?

There could be several reasons for this. Some common mistakes include forgetting to factor out common factors, making errors in the signs of the terms, or not using the correct method for decomposition. It is important to double-check your work and review the correct steps for decomposing a polynomial.

What are the key steps for decomposing a polynomial?

The key steps for decomposing a polynomial are: 1) factor out any common factors, 2) use the correct method for decomposition (such as factoring by grouping or using the difference of squares formula), and 3) check your work by multiplying the decomposed terms to ensure they equal the original polynomial.

Can I use different methods for decomposing a polynomial?

Yes, there are various methods for decomposing a polynomial, such as factoring by grouping, using the difference of squares formula, or using the quadratic formula. It is important to choose the method that is most suitable for the polynomial you are working with.

What are some common mistakes to avoid when decomposing a polynomial?

Some common mistakes to avoid when decomposing a polynomial include forgetting to factor out common factors, making errors in the signs of the terms, and not using the correct method for decomposition. It is also important to carefully check your work for any errors before finalizing the decomposition.

Similar threads

Back
Top