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Math Help - implied domain

  1. #1
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    implied domain

    Hey MHF: Ive just got a question on the implied domain.
    f(x)= Square root(x^2 - 3)

    easy question i just need an somebody to clarify how to solve it.

    Cheers
    Andrew
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  2. #2
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by RoboStar View Post
    Hey MHF: Ive just got a question on the implied domain.
    f(x)= Square root(x^2 - 3)

    easy question i just need an somebody to clarify how to solve it.

    Cheers
    Andrew
    the domain of \sqrt{x} is x \ge 0 for x \in \mathbb{R}. thus, the implied domain here is given by: x^2 - 3 \ge 0
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  3. #3
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    and another question

    h(x) = square root(x - 4) + square root(11 - x)
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by RoboStar View Post
    and another question

    h(x) = square root(x - 4) + square root(11 - x)
    you just have to make sure x - 4 \ge 0 and 11 - x \ge 0 work at the same time. choose the values of x that satisfy both
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  5. #5
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    thanks for all your help just two more questions on implied domain

    f (x) = x^2 - 1 / x + 1 and h (x) = square root(x-1/x+2)
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by RoboStar View Post
    thanks for all your help just two more questions on implied domain

    f (x) = x^2 - 1 / x + 1 and h (x) = square root(x-1/x+2)
    okay, for rational functions, we have the condition that we cannot divide by zero. and you know the condition for square roots. so there are three conditions you want to fulfill here

    for f(x): you want x + 1 \ne 0

    for h(x): you want \frac {x - 1}{x + 2} \ge 0 (for the square root) and x + 2 \ne 0 (for the rational function being square rooted)

    of course, for h(x), both conditions must be fulfilled at the same time. so find the x's that work for both simultaneously
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