Sine Wave Functions

Discussion in 'Homework Help' started by m4yh3m, May 13, 2004.

  1. m4yh3m

    Thread Starter Senior Member

    Apr 28, 2004
    186
    39
    if a sine wave is

    f(x)=sin x

    x = phase?
     
  2. haditya

    Senior Member

    Jan 19, 2004
    220
    0
    yes.. x is the phase
    usually phase is the measure of time lead or lag of a wave/particle with respect to another measured to an reference(origin).. for mathematical purposes it is measure in terms of and angle.
     
  3. Dave

    Retired Moderator

    Nov 17, 2003
    6,960
    143
    x is not the phase, x is the variable of the function as you have defined f(x).

    If you look at the following function:

    f(x) = Sin (Θ±φ)

    Where x = (Θ±φ)

    Θ is the angle which is subdefined in the context of your function (for example, for a phasor Θ = ωt)

    And φ is the phase.
     
  4. m4yh3m

    Thread Starter Senior Member

    Apr 28, 2004
    186
    39
    so what's the difference between

    f(x)= Vpk sin Θ
    f(x)= Vpk sin ωt
    f(x)= Vpk sin (ωt +Θ)

    ?
     
  5. Dave

    Retired Moderator

    Nov 17, 2003
    6,960
    143
    Just the notation.

    In all examples you have defined x as the variable, however you need to say the following for the expression to make sense:

    1) x = Θ

    2) x = ωt

    3) x = ωt ± Θ (although in this example you have defined the phase with Θ, which is not considered standard practice, generally use φ or ø)

    However it is not really correct to define f(x) in this way as you are declaring x as a variable of the function where the function operates in other terms, i.e. Θ, t, ω and φ (this is more my fault for using this notation in my previous reply). More precisely, you should say:

    v(t) = Vpk Sin (ωt ± φ)

    Which says the sinusoidal voltage operates as a function of time with angular velocity ω and phase angle φ.
     
  6. m4yh3m

    Thread Starter Senior Member

    Apr 28, 2004
    186
    39
    thank you very much for the clarification.
     
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