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Vector transformation

  1. Apr 22, 2004 #1
    what does it mean by applying vector <-1,-1> to translate f(x) to h(x)?
     
  2. jcsd
  3. Apr 23, 2004 #2

    HallsofIvy

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    "Translation" in general means to add a vector. Since you haven't told us what "f(x)" and "h(x)" represent I can't be more specific but if they are vector valued functions, then I would suspect you are to add the vector <-1,-1> to f(x).
     
  4. Apr 23, 2004 #3
    f(x)=x^3-3x^2
    h(x) should be in the form of ax^3+bx^2+cx+d

    edit: problem solved. Thanks.
     
    Last edited: Apr 25, 2004
  5. Apr 26, 2004 #4

    HallsofIvy

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    I suspect that you are intended to find a function whose graph looks exactly line y= f(x) but is translated (one translates geometric things- points and sets of points like graphs- not functions) by <-1,-1>. In particular, that means that, since f(0)= 0, we want g(-1)= -1. First, we want x= -1, in g, to "act like" x=0 in f. That is
    g(x)= f(u) for some u so that when x= -1, u= 0: okay the simplest possible thing is u= x+1. If we write g(x)= f(x+1)= (x+1)3- 3(x+1)2, we have g(-1)= f(0) but we are not quite done: g(-1)= f(0)= 0 and we want g(-1)= f(0)-1. Fine: just subtract 1 from what we just got:

    g(x)= (x+1)3- 3(x+1)2- 1.

    In order to get it in the form "ax3+ b2+ cx+ d", you will need to multiply it out.
     
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