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    For part b, I thought the domain of f o f is all real numbers except -5 but it states that the right answer is all real numbers except -5 and 2.



    I realised that if x = 2, then f o f = 3 and I can see where this is going but I don't have as clear an idea of the concept in play here as I'd like. Could someone explain this to me in detail, please?

    EDIT : Is this it?

    If the domain included x = 2, then f o f = 3. But if f o f = f[f(x)] = 3, then, f(x) = f^{-1}(3) But this is not possible since f^{-1}(x) cannot take the value 3 since 3 is not a part of the domain of f^{-1}(x)

    Thank you!

    Sid
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    (Original post by Sidhant Shivram)


    For part b, I thought the domain of f o f is all real numbers except -5 but it states that the right answer is all real numbers except -5 and 2.



    I realised that if x = 2, then f o f = 3 and I can see where this is going but I don't have as clear an idea of the concept in play here as I'd like. Could someone explain this to me in detail, please?

    Thank you!

    Sid

    x=2 cannot go in the first "stage"
    x=-5 cannot go in the second stage.
    You can see this in the denominator or set the function = 2 gives -5
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    Okay. Got it.Thanks!
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    (Original post by Sidhant Shivram)
    Okay. Got it.Thanks!
    no worries
 
 
 
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