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Does cos^2(kt)+sin^2(kt)=1?

  1. Jul 27, 2014 #1
    Where k is a constant.

    I am trying to simplify a problem but the t has constant in front of it that is not one, and I can't seem to find a chart that verifies it either way.
     
  2. jcsd
  3. Jul 27, 2014 #2
    Yes. cos2θ + sin2θ = 1 for any value of θ, including θ = kt. This is called the Pythagorean identity, and is the result of applying the Pythagorean theorem to the fact that cosθ and sinθ are the x and y coordinates, respectively, of a point on the unit circle (a circle of radius 1).
     
  4. Jul 27, 2014 #3
    Thanks!
     
  5. Jul 28, 2014 #4
    Thanks!

    ...is a brilliant answer to my problem of how to describe force vectors for alloys. Big thanks, slider142. and mill.
     
  6. Jul 28, 2014 #5
    Just got back from seaside and found answer to a month's headache. Complementary! B)
     
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