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!

What did I do wrong here? (expressing root x as taylor series about a=4)

  1. Mar 16, 2012 #1
    1. The problem statement, all variables and given/known data

    Here is the question:

    nxh3n.png

    I don't quite know what I did wrong. My method is below.

    2. Relevant equations



    3. The attempt at a solution

    f(x)=√x
    f'(x)=[itex]\frac{1}{2(x)^{1/2}}[/itex]
    f''(x)=[itex]\frac{-1}{(2)(2)(x^{3/2}}[/itex]

    a=4
    f(a)=2
    f'(a)=1/4
    f''(a)=[itex]\frac{-1}{4(4^{3})^{1/2}}[/itex]

    so wouldn't the second taylor polynomial be what I put in the answer field above? Thanks.
     
  2. jcsd
  3. Mar 16, 2012 #2

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    What you have is the degree 2 term (almost). What's the sign?

    Include the constant term & the linear term.
     
  4. Mar 16, 2012 #3
    Oh, so if it asks for T[itex]_{2}[/itex] it also wants the T[itex]_{1}[/itex] and the constant term as well?

    Also, I see now that I somehow dropped a negative sign. Thanks!

    EDIT: I just tried it and it's correct, so I answered my own question. But thanks again!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: What did I do wrong here? (expressing root x as taylor series about a=4)
  1. What did I do wrong (Replies: 1)

  2. What did I do Wrong? (Replies: 7)

Loading...