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: Point of inflection question

  1. Oct 25, 2006 #1
    Hi guys... I have this problem that i need to verify. I did it but i just want one of you guys to maybe check to see if it is correct.

    problem: find the points of inflection on the curve

    y = -3x^4 + 4x^3 +36x^2

    so first i found y'' = -36x^2 + 24x + 72 = 0
    since b^2 - 4ac is not a perfect square i had to use the formula
    x = [ -b + sqrt(b^2 - 4ac) ]/2a
    x = [ -b - sqrt(b^2 - 4ac) ]/2a

    by using these i get the values of x as
    x = -1.1196
    and x = 1.7863

    so the points of inflection are (-1.1196, 34.79) and (1.7863, 107.12)

    Thanks in advance
  2. jcsd
  3. Oct 25, 2006 #2
    Perfect :).
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook