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: Maclaurin Polynomial function

  1. Dec 7, 2012 #1
    1. The problem statement, all variables and given/known data

    I'm having a bit of trouble with this Maclaurin Series question. It should be simple enough but I can't get the answer which is given as x2. It's been a while since i've done series and my being rusty is a little annoying. Hopefully someone can help :) Consider:


    Question asks to find the Quadratic Maclaurin Polynomial for f(x).
    So this is what I did. First I got the nth derivatives:

    f1(x) = x*cos(x) + sin(x)
    f2(x) = -x*sin(x) + cos(x) + sin(x)

    P2(x): 0 + x*0 + (x^2)(0 + 1 + 0)*(1/2!)

    = x2/2

    I'm sure i'm doing something blatantly wrong here but I can't seem to work it out. Fresh eyes might be useful :)

    Thanks a lot.
  2. jcsd
  3. Dec 7, 2012 #2
    Oh no.. it was the derivative.. lol i've been racking my brain for 20 minutes staring at Taylor's Theorem thinking I made the error there.. ugh well that's embarrassing.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook