1. Limited time only! Sign up for a free 30min personal 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!

Range of a f(x) involving floor

  1. Mar 12, 2009 #1
    1. The problem statement, all variables and given/known data
    I have to find the range of f(x) where:
    f(x)=7*floor(x) - floor(7*x)
    x is a real number.

    Then I have to prove that this set of numbers is correct.

    3. The attempt at a solution
    I am still on the range part, and thus am only asking about that part at the moment. It seems to me that the range of f(x) would be (-infinity,+infinity). Is there a reason that it wouldn't be?
  2. jcsd
  3. Mar 12, 2009 #2
    Sketch the graphs of g(x) = 7*floor(x) and h(x) = floor(7x) on the same paper.
  4. Mar 12, 2009 #3
    Ah yes, back to basics for me.

    Ok so it seems that all possible values of f(x) are:

    thus range of f(x) = (-6,0).

    Last edited: Mar 12, 2009
  5. Mar 12, 2009 #4
    what does that round thing at the end of question #4 a and #4 b mean sneakyArab
  6. Mar 12, 2009 #5
    seems I've found a classmate.

    I'm not sure if you mean the last symbol or next to last, so after the equation it reads:

    "is not rational"

    so its not a rational number.
  7. Mar 12, 2009 #6
    I think I have a working proof on this one now. Thanks for getting me started Slider!
  8. Mar 12, 2009 #7
    thanks man it looks all crazy i couldnt figure it out
    good luck and thanks again
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook