How do I show that a derivative of a polynomial has a zero in an interval?

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SUMMARY

The discussion focuses on proving that the (2n-1)th derivative of an even degree polynomial intersects the x-axis within an interval where the polynomial itself intersects the x-axis twice. The example provided, g(x) = x^3(1-x), illustrates that g'''(c) = 0 for some c in (0, 1) without direct computation. The key takeaway is that the behavior of derivatives at critical points, such as maxima and minima, guarantees the existence of zeros in the derivatives within specified intervals.

PREREQUISITES
  • Understanding of polynomial functions and their properties
  • Knowledge of derivatives and critical points
  • Familiarity with the Mean Value Theorem
  • Concept of even and odd degree polynomials
NEXT STEPS
  • Study the Mean Value Theorem and its implications for derivatives
  • Explore the relationship between critical points and the existence of zeros in derivatives
  • Investigate the properties of even degree polynomials and their derivatives
  • Learn about Rolle's Theorem and its applications in proving derivative behavior
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Students studying calculus, particularly those focusing on polynomial functions and their derivatives, as well as educators looking for examples of derivative behavior in mathematical proofs.

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Homework Statement



If an even degree polynomial of order 2n intersects the x-axis twice, how do I show that the (2n-1) th derivative has a zero in that interval?


Homework Equations



example: let g(x)=x^3(1-x). Show without computation that g'''(c) =0 for some c in (0, 1).

The Attempt at a Solution



I know that g' has a zero at x=1/2 because that is a maximum. I don't know how I can be sure that the 2nd and 3rd derivative have a zero in this interval.
 
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consider what happens to terms less of order (2n-2) and less...
 

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