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Trigonometric function help

  1. Sep 7, 2005 #1
    f(x)= sin 3x - (1/2)sin x, find the period.

    i know the period for sin 3x is 2pi/3 and the period of sin x is 2pi but how do you subtract these? I totally forget how to do this! I mean i could find the answer with any graphing program but i want to know how to do this type of problem.
  2. jcsd
  3. Sep 7, 2005 #2
    Go with the greater value (period). Can you see why?
  4. Sep 8, 2005 #3


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    Science Advisor

    Why subtract them? The two functions will both repeat when you reach the least common multiple of their separate periods. Here, it should be obvious that [tex]2\pi[/tex] is a multiple of [tex]\frac{2\pi}{3}[/tex].
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