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: Find the equation of the curve

  1. Nov 7, 2011 #1
    1. The problem statement, all variables and given/known data
    From the given sequence of numbers (11.25, 10, 9.25, 9, 9.25, 10, 11.25, 13, 15.25, 18 ...)
    A) Graph the sequence
    B) Find the equation of the curve
    C) Determine the 100th term of the sequence

    2. Relevant equations

    3. The attempt at a solution
    I know how to graph the sequence by setting the given numbers as y coordinates and their order as x coordinate but beyond there I'm stuck. Help please!
  2. jcsd
  3. Nov 7, 2011 #2


    Staff: Mentor

    There is a certain pattern that jumps out here. Look at the difference of successive terms in this sequence.

    Also, the second differences are constant.
  4. Nov 7, 2011 #3
    I can see the pattern but I don't know how to apply it in the equation of the curve. Is there a formula I can plug the data into to find the equation?
  5. Nov 7, 2011 #4
    is the curve the same thing as a parabola?
  6. Nov 7, 2011 #5


    Staff: Mentor

    The curve might be a parabola. If so, you know where the vertex is.

    In case it's not a parabola, there's an area of mathematics called Difference Equations (see http://en.wikipedia.org/wiki/Recurrence_relation) that might be helpful. See especially the section titled "Relationship to difference equations narrowly defined."
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook