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GRE Practice Question

  1. Mar 13, 2010 #1
    Let k be the number of real solutions of the equation e[tex]^{x}[/tex] + x - 2 = 0 in the interval [0,1] and let n be the number of real solutions that are not in the interval.

    By looking at the graph, I know it crosses the x axis; however, I don't remember or know how to do this problem.
     
  2. jcsd
  3. Mar 13, 2010 #2

    LCKurtz

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    Hint: If f(x) = ex + x - 2, look at f(0), f(1) and f '(x).
     
  4. Mar 13, 2010 #3
    I know what f(0) and f(1) are and f '(x) = e[tex]^{x}[/tex] + 1

    How is that suppose to help?
     
  5. Mar 13, 2010 #4

    LCKurtz

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    You mean "supposed" to help.

    What does the fact that f(0) and f(1) have opposite signs tell you? What does having a positive derivative tell you? And, of course, I'm just assuming I know what your actual question was since your original post doesn't actually contain a question. :confused:
     
  6. Mar 13, 2010 #5
    At least this isn't an English forum. The question was in regards to multiple choices so I left that out because it wasn't needed.
     
  7. Mar 13, 2010 #6

    LCKurtz

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    No extra charge for the English.

    How are we supposed to know what the question was if you don't tell us? So, what was the question? And did the hints I gave you help you solve it?
     
  8. Mar 13, 2010 #7
    The question said which of the following. I didn't need someone to tell me which one it was so I left it out.
     
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