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Homework Help: Sin() function problem

  1. Aug 20, 2008 #1
    f(x) = 9 sin 7 x, and g(x) = 18 sin(7 x + 5)

    so, i assume by looking just like this g(x) is twice much more than f(x) and 5 units more, correct??
  2. jcsd
  3. Aug 20, 2008 #2
    Re: sin

    What do you mean by twice much more and 5 units more? You need to figure out what each of the factors in f(x) = A*sin(Bx + C) + D does, for example, A is the amplitude, 2pi/B is the period, now think as to what C and D are.
  4. Aug 20, 2008 #3
    Re: sin

  5. Aug 20, 2008 #4


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    Re: sin

    If you're wondering how much the g(x) is shifted relative to f(x), it's not 5 units. But yes, the amplitude is twice as much.

    To get the shift, rewrite g(x) as

    g(x) = 2f(x-h)


    18 sin (7x - 5) = 2*9 sin(7(x-h))

    What mus h be, to make those expressions equal?
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