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Math Help - inverse one-one functions

  1. #1
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    after finding the inverse of a function algebraically how can you tell if its one-one without graphing on ti-83 and doing the horizontal line test?

    take for instance the problem f(x)=3x+4/5

    for the inverse i got 5x-4/3=y

    from this how do i find the if its one-one without graphing
    Last edited by mr fantastic; September 12th 2009 at 03:17 PM. Reason: Merged posts
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  2. #2
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    Quote Originally Posted by purified View Post
    take for instance the problem f(x)=3x+4/5
    for the inverse i got 5x-4/3=y
    from this how do i find the if its one-one without graphing
    Well all linear equations are one-to-one.
    Beyond that, you will learn how to do this in basic calculus.
    But in pre-calculus it is very difficult.
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  3. #3
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    Your function is linear. All linear functions are one to one.

    You should learn the shapes of each polynomial x^n where n \in \mathbb{J}
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  4. #4
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    like i understand f(x)=1/x^2 can not be one to one because x^2 will always be positive f(1)=f(-1)=1 but what about like:

    f(x)=x^4
    inverse: y=plus or neg nth root 4 squareroot X
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