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Homework Help: What is the frequency of the sum of several sine waves?

  1. Sep 4, 2015 #1
    • Member warned about posting without the HW template
    I am given three sine waves with individual frequency being 10 Hz, 50 Hz, and 100 Hz.
    What is the frequency of the following :

    y(t) = sin(2π10t) + sin(2π50t) + sin(2π100t)​

    Is it simply 100, the LCM of all the sin waves? If not, How to calculate the frequency of y(t) ?​
  2. jcsd
  3. Sep 4, 2015 #2


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    Homework Helper
    Gold Member

    I would say 10Hz, the HCF of the frequencies.
    All three frequencies are still present, combining to give a non-sinusoidal waveform. This combined waveform is periodic over 0.1sec, due to the 10Hz component.
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