Corpus ID: 115170901

A New Approach to Rational Values of Trigonometric Functions

@inproceedings{Dresden2009ANA,
  title={A New Approach to Rational Values of Trigonometric Functions},
  author={Gregory P. Dresden},
  year={2009}
}
It is well known that sin(a\pi/b), cos(a\pi/b), etc., are only rational numbers for a few select integers a and b. We show that this is equivalent to the fact that only for d = 1,2,3,4, and 6 is the primitive dth root of unity of degree 2 over Q. 

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References

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