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Homework Help: Taylor polynomials

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

    Find the degree 3 Taylor polynomial approximation to the function f(x)=5ln(sec(x)) about x=0.


    2. Relevant equations

    the taylor polynomial equation

    3. The attempt at a solution

    Here are my derivatives
    f(x)=5ln(secx)
    f'(x)=5tanx
    f''(x)5sec^2(x)
    f'''(x)=10sec^2(x)tanx

    Please let me know if any of the above are wrong

    When I try to plug in 0 for the x's above I end up with a whole lot of undefined answers because sec0=undefined. How can I get around this?

    thanks
     
  2. jcsd
  3. Nov 1, 2012 #2
    Are you sure that [itex]sec 0 = \frac{1}{cos 0}[/itex] is undefined?
     
  4. Nov 1, 2012 #3
    oops, got sec and csc confused. Thanks
     
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