1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Vector question confusion

  1. Mar 9, 2007 #1
    hi, i'm basically a bit confused as to how to solve this vector question, in other words, in what i have to do which is confusing me...

    1. The problem statement, all variables and given/known data

    This is a sketch of the curve with equation y = f(x)
    It passes through the origin O.

    (the sketch has no value on or anything, its simply a happy parabola then passes through the origin on the left side a bit of the way up, and dips in the negative y values)

    The only vertex of the curve is at A (2, -4)

    a) Write down the coordinates of the vertex of the curve with the equation (bold are my answers)

    i) y = f(x-3) (5, -4)
    ii) y = f(x) -5 (2, -9)
    iii) y = -f(x) (2, 4)
    iv) y = f(2x) (1, -4)

    The curve with equation y=x^2 has been translated to give the curve y=f(x)[/]

    b) find f(x) in terms of x

    2. Relevant equations

    (I dunno if the first half of the question is needed, if it is, say so and ill post it up)

    3. The attempt at a solution

    not really sure, i know how functions work, I know all about vectors too, but not sure what it means by "translated", and how i would find out the answer.

    my instinct says the answer is simply x^2, but somehow I dont think it is, and i certainly dont think that is worthy of 4 marks :S


    hope you can help, thnx


    i added in the entirity of the question now..
     
    Last edited: Mar 9, 2007
  2. jcsd
  3. Mar 9, 2007 #2

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Translated how? The question as posted doesn't make much sense. Better post the rest.
     
  4. Mar 9, 2007 #3
    ok

    ill add it to the main topic
     
  5. Mar 9, 2007 #4
    added to the topic the entirity of the question, hope that helps
     
  6. Mar 9, 2007 #5

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Ok, so y=f(x) is a parabola going through the origin with a vertex at (2,-4) and you want to find its equation given that its a translation of y=x^2? Well, you want to move it two units right and four units down. Having done part a) you should be able to manage that. What's your guess?
     
  7. Mar 9, 2007 #6

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    That, together with the fact that it is a "happy" (I like that!) parabola with vertex (2, -4) tells you that y= a(x-2)2- 4 for some positive number a.

     
  8. Mar 10, 2007 #7
    o rite, see how the answer is y=f(x-2)+4 now, but one thing i a tad confused on

    the a you refer to, thats the stretching and stuff yeh, and just to check, is the reason you came to the conlusion that it has to be 1, because it said y = x^2 is translated. does that term translated refer specificially to it moving not being strechted or whatever?

    thnx for the help
     
  9. Mar 10, 2007 #8

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    Yes, in connection with movement (as opposed to translating a language!) means a movement with no stretching or rotating.

    By the way, why did you title this "vector question confusion" (and refer to it as a "vector question" in your post) when there are no vectors involved?
     
  10. Mar 10, 2007 #9

    oops haha, yeh i realised what i did


    basically, i was stuck writing a vector problem in the topic, but then i figured out what i was doing, then went onto to the next question (this question), and forgot to change the topic title hehe

    oops
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Vector question confusion
  1. Vector question (Replies: 2)

  2. Vector Questions (Replies: 2)

  3. Vectors question (Replies: 4)

Loading...