C3 maths exponential functions

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    Can anyone help? I have drawn the function ln x and transformed it using the transformation rules. However, I have drawn ln (-x) and that doesn't seem to follow the transformation rules. Anyone know why?
    Thanks
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    It does,y = ln(-x) is a reflection in the y axis of the curve y=ln(x)
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    (Original post by peterhw)
    Can anyone help? I have drawn the function ln x and transformed it using the transformation rules. However, I have drawn ln (-x) and that doesn't seem to follow the transformation rules. Anyone know why?
    Thanks
    Depends on the transformation you're trying to perform. If it's a reflection in the y-axis (x=0), then well done you got it.
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    I should maybe ha e been clearer. If I plot ln(X+4) ln X moves left 4 but if I plot ln(-X+4) then ln(-X) moves right 4. Why is that?
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    (Original post by peterhw)
    I should maybe ha e been clearer. If I plot ln(X+4) ln X moves left 4 but if I plot ln(-X+4) then ln(-X) moves right 4. Why is that?
    It doesn't work like that.

    \ln(x) \Rightarrow \ln(x+4) is a translation by vector [-4,0] (so you got that bit correct)

    \ln(x) \Rightarrow \ln(-x+4) is a translation by vector [-4,0] followed by a reflection in the y-axis.

    Translation by vector [4,0] would be represented by \ln(x) \Rightarrow \ln(x-4) which is not the same as \ln(-x+4)
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    (Original post by peterhw)
    I should maybe ha e been clearer. If I plot ln(X+4) ln X moves left 4 but if I plot ln(-X+4) then ln(-X) moves right 4. Why is that?
    This gets asked a lot, look at post 11, credit goes to Zacken for this good explanation.
    http://www.thestudentroom.co.uk/show...4#post67429014
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    (Original post by RDKGames)
    It doesn't work like that.

    \ln(x) \Rightarrow \ln(x+4) is a translation by vector [-4,0] (so you got that bit correct)

    \ln(x) \Rightarrow \ln(-x+4) is a translation by vector [-4,0] followed by a reflection in the y-axis.

    Translation by vector [4,0] would be represented by \ln(x) \Rightarrow \ln(x-4) which is not the same as \ln(-x+4)
    Thank you
 
 
 
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