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: Plotting Two Variables

  1. Sep 21, 2012 #1

    The question is the following:

    Another student proposes that c is proportional to d0.5 State a suitable graph that can be plotted to test this proposal.

    I suggested plotting log c = 0.5 log d.

    One of the answers the markscheme accepts is log c = log d

    Can anyone tell me why my answer is wrong?

  2. jcsd
  3. Sep 22, 2012 #2
    Inversely proportional or directly proportional ?

    Is c directly proportional to d1/2 ? If so , then equation cannot be log c = 0.5 log d.

    Anyways what's precisely is question asking for ? Your answer seems to be wrong because you missed the constants involved in proportionality.
  4. Sep 22, 2012 #3
    It is supposed to be directly proportional I guess, since they want a straight line through the origin.

    I just don't understand how you can get lg c = lg d like the mark scheme asks for
  5. Sep 22, 2012 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    The mark scheme appears to be wrong. Perhaps the person who wrote it accidentally left out the 0.5 factor.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook