10170

# n-gon Polynomials

Consider these polynomials:
5-gon:
7-gon: =
17-gon:
The 5-gon polynomial has roots ,,, }, where is the golden ratio. Any one of these values can be used to construct a regular pentagon. The construction of a regular 17-gon (or heptadecagon) requires any root of the 17-gon polynomial. Gauss, as a teenager, showed that nested square roots can solve the 17-gon polynomial, making the 17-gon classically constructible. He also proved that roots of the 7-gon polynomial are not classically constructible. Curiously, any cubic equation can be solved with origami, making the heptagon origamically constructible.
The -gon polynomial is , a Chebyshev polynomial of the second kind. The graphs shown are of the factors of this Chebyshev polynomial.

### PERMANENT CITATION

 Share: Embed Interactive Demonstration New! Just copy and paste this snippet of JavaScript code into your website or blog to put the live Demonstration on your site. More details » Download Demonstration as CDF » Download Author Code »(preview ») Files require Wolfram CDF Player or Mathematica.

#### Related Topics

 RELATED RESOURCES
 The #1 tool for creating Demonstrations and anything technical. Explore anything with the first computational knowledge engine. The web's most extensive mathematics resource. An app for every course—right in the palm of your hand. Read our views on math,science, and technology. The format that makes Demonstrations (and any information) easy to share and interact with. Programs & resources for educators, schools & students. Join the initiative for modernizing math education. Walk through homework problems one step at a time, with hints to help along the way. Unlimited random practice problems and answers with built-in Step-by-step solutions. Practice online or make a printable study sheet. Knowledge-based programming for everyone.