MHB How Do Vieta's Formulas Apply to Cubic Polynomial Roots?

  • Thread starter Thread starter Mathsonfire
  • Start date Start date
  • Tags Tags
    Cubic Polynomial
AI Thread Summary
Vieta's formulas provide relationships between the coefficients of a cubic polynomial and its roots, allowing for the calculation of sums and products of the roots. The expressions for the sums of pairs of roots, such as $(\alpha+\beta)+(\alpha+\gamma)+(\beta+\gamma)$, can be derived using these formulas. Additionally, the product of sums of pairs of roots, represented by $(\alpha+\beta)(\alpha+\gamma)(\beta+\gamma)$, can also be evaluated through Vieta's relationships. Another expression, $(\alpha+\beta)(\alpha+\gamma)+(\beta+\gamma)(\alpha + \beta)+(\alpha+\gamma)(\beta+\gamma)$, showcases further applications of Vieta's formulas in understanding cubic polynomials. Overall, these discussions highlight the utility of Vieta's formulas in analyzing the relationships between roots of cubic polynomials.
Mathsonfire
Messages
11
Reaction score
0
88
e2dbcd89be56845ac60cd1e86e4c9430.jpg
 
Mathematics news on Phys.org
You can read $\alpha + \beta + \gamma $, $\alpha\beta +\alpha \gamma + \beta \gamma$ and $\alpha \beta \gamma$ off from the polynomial.

Now what's $(\alpha+\beta)+(\alpha+\gamma)+(\beta+\gamma)$?

And what's $(\alpha+\beta)(\alpha+\gamma)(\beta+\gamma)$?

And finally $(\alpha+\beta)(\alpha+\gamma)+(\beta+\gamma)(\alpha + \beta)+(\alpha+\gamma)(\beta+\gamma)$?Those questions all seem to be an exercise in Vietas formulas.
 
Last edited:
Seemingly by some mathematical coincidence, a hexagon of sides 2,2,7,7, 11, and 11 can be inscribed in a circle of radius 7. The other day I saw a math problem on line, which they said came from a Polish Olympiad, where you compute the length x of the 3rd side which is the same as the radius, so that the sides of length 2,x, and 11 are inscribed on the arc of a semi-circle. The law of cosines applied twice gives the answer for x of exactly 7, but the arithmetic is so complex that the...

Similar threads

Back
Top