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!

Homework Help: A question on notation - R^1, R^2, ,R^n

  1. May 2, 2010 #1
    Hello everyone,

    What does my professor mean when he says x belongs in [tex]R^{n}[/tex]. What is [tex]R^{n}[/tex]?

    Does [tex]R^{1}[/tex] mean 1-variable? or 2-dimension (just a line)? or both?

    What about [tex]R^{2}[/tex]? is this 2 variable? or 3-dimension? both?

    Thank you for your help.

  2. jcsd
  3. May 2, 2010 #2
    Well [tex] R [/tex] usually just denotes the real plane as opposed to [tex] C [/tex] which is the complex plane. if you have [tex] R^{2} [/tex] and [tex] R^{3}[/tex] it could be different sets in set theory but I am not sure what you are working on right now. Depending on the subject of study it could be completely different than that.
  4. May 2, 2010 #3


    Staff: Mentor

    R or R1 is a one-dimensional space of real numbers - the real number line. A single coordinate suffices to locate a point on a line. You are apparently confused about the dimension of a line.

    R2 or R X R is a two-dimensional space of pairs of real numbers - the real plane. A point or vector in R2 has two coordinates.

    R3 or R X R X R is a three-dimensional space of triples of real numbers. A point or vector in R3 has three coordinates.

    Rn is an n-dimensional space of n-tuples of real numbers. A point or vector in Rn has n coordinates. Although we have a hard time imagining spaces of more than three dimensions, most of the concepts we understand from one-, two-, or three-dimensional space extend naturally to a space of n dimensions.
  5. May 2, 2010 #4


    Staff: Mentor

    No, R does not represent the real plane.
  6. May 2, 2010 #5
    real number line/set of real numbers. sorry
  7. May 2, 2010 #6
    Excellent, thanks guys.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook