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I need help

  1. Aug 28, 2005 #1
    Let f(x)=x+|x| and g be defined by the rule "g(x) is the slope of the graph pf f at x".

    Write f as piecewise defined function. :confused:
  2. jcsd
  3. Aug 28, 2005 #2
    Can I write it just like

    f(x)={ x+|x| if x>1
  4. Aug 28, 2005 #3


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    Where x > 0, you get f(x) = 2x.
    Where x < 0, you get f(x) = 0.

    Does that help?
  5. Aug 28, 2005 #4
    O, got you. Thanks.
  6. Aug 28, 2005 #5


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    Minor point: don't forget x = 0 in your definition. :smile:
  7. Aug 28, 2005 #6
    So should I put that also?
  8. Aug 28, 2005 #7


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    Make the first one [tex] \ge [/tex] then ;o)
  9. Aug 28, 2005 #8
    And If I want to find g I use derivative???
  10. Aug 28, 2005 #9


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    Sure, you could do that. Should be quite simple in this case!
  11. Aug 28, 2005 #10
    Yeah. Thanks for help.
  12. Aug 28, 2005 #11
    Just remember that your derivative doesn't exist at x=0. I've gotten points taken off because I wrote the derivative with less than or equal signs, even though it's supposed to have just a less than sign.
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