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Math Help - Function Help

  1. #1
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    Function Help

    I do not understand how to answer this question:

    f(x) = 1
    x + 2

    a) find the value of x which must be excluded from the domain of f(x)

    b) find the inverse function f-1 (x)

    Help would be appreciated on either question
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  2. #2
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    earboth's Avatar
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    Quote Originally Posted by abbie1212 View Post
    I do not understand how to answer this question:

    f(x) = 1
    x + 2

    a) find the value of x which must be excluded from the domain of f(x)

    b) find the inverse function f-1 (x)

    Help would be appreciated on either question
    a) The term of the function is a fraction. Keep in mind that the division by zero is not allowed.

    b) Take the equation y = f(x). That means

    y=\frac1{x+2}

    Now swap the variables x and y and solve for y again.
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  3. #3
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    Dear abbie1212,

    I assume you have written, f(x)=1/(x+2)

    Now you could see that this function does not have a value when x=-2.
    (f(x)would be infinite.) Therefore x=-2 must be excluded from the domain of f.
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  4. #4
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    Thanks, but still a bit confused, what is the answer and how?
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  5. #5
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    Quote Originally Posted by abbie1212 View Post
    Thanks, but still a bit confused, what is the answer and how?
    what answer? the question about the function's domain or its inverse?
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