1. Not finding help here? Sign up for a free 30min 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!

Review in calc I to prepare for calc II

  1. Jan 9, 2006 #1


    User Avatar
    Gold Member

    I'm doing a review in calc I to prepare for calc II. I'm now applications of derivatives (optimization). Okay so when I have the function I need to optimize, I need to take the derivative and find the critical point of the first derivative. But sometimes theres more than one critical point. Is there any sort of test that I can do to find which critical point I should use.

    --thank you.
  2. jcsd
  3. Jan 9, 2006 #2
    Why not a first derivative test? I assume you have done one before. If the derivative is negative until the critical point, then positive after the critical point then you have a maximum. The other way around for a minimum. Essentially limits with derivatives.
  4. Jan 9, 2006 #3


    User Avatar
    Gold Member

    Ah the first derivative test. Thanks for the input.
  5. Jan 9, 2006 #4
    Other way around, if the derivative is negative to the critical point and the positive after the value at that point is a minimum, because the function decreases to that point and then increases.
  6. Jan 10, 2006 #5
    You could also get the second derivative and evaluate it in the critical points (where the first derivative is zero). If the second derivative is negative you have a maximum, if it's positive you have a minimim and if it's zero you have (what i directly translate from dutch, because I don't know what it's called in english) a bending point, as you would have in the function y=x^3. If calculating the second derivative isn't too much work, I generally use this method to establish the nature of a critical point.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Review in calc I to prepare for calc II
  1. Review for calc 3 (Replies: 0)

  2. Calc II Suggestions (Replies: 3)

  3. Calc II (Replies: 8)

  4. Calc Book That I Have (Replies: 10)