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Homework Help: Sketching a graph

  1. Oct 10, 2007 #1
    1. The problem statement, all variables and given/known data
    Sketch the graph of f(x)=x^3 + 1/x

    2. Relevant equations

    3. The attempt at a solution
    The only way I could think of doing this was by creating a table of values which I did, my graph came out decently close to the real thing (checked on graphing calculator), we did not learn how to use derivatives to find the increasing and decreasing part so how else would I go about doing this?
  2. jcsd
  3. Oct 10, 2007 #2


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    Homework Helper

    Well at a stationary point...the first derivative is zero i.e. f'(x)=0.

    That will allow you find any stationary point...to find whether it is maximum or minimum points

    say you got [tex](x_1,f(x_1))[/tex] as a stationary point then you'd find [tex]f''(x_1)[/tex] and if it is +ve then that point is a min. but if it was -ve then it is a max.

    also you should check what happens as [tex]x\rightarrow \pm\infty,0[/tex]
  4. Oct 11, 2007 #3
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