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Math Help - domain/range help

  1. #1
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    domain/range help

    Hey guys!

    I have 2 equations:
    f(x) = sin x
    g(x) = x^2 - x + 1

    The question asks to find fg(x) and f/g(x) (and domain/range for each)

    for fg(x) i got:
    fg(x) = sin x^3 - sin x^2 + sin x

    how would i find the domain and range for this?

    and for f/g(x) i got:
    f/g(x) = (sin x) / (x^2 - x + 1)

    I don't think that can be reduced anymore, but correct me if i'm wrong. And I need help finding the domain and range for this equation too.
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  2. #2
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    Domain and Range normally are easier to determine by assuming ALL REAL NUMBERS and only then looking around for things that really are not included.

    f(x) = sin(x)

    All Real Numbers.
    Nothing to throw out.
    Done.

    g(x) = 1/sin(x)

    All Real Numbers
    Wait, sin(x) can be zero. We had better avoid x = k\pi where k is an integer.
    Done.

    Okay, now you do one.
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  3. #3
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    thanks! I never thought of it like that!
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