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Graphing a exponential problem

  1. Jan 23, 2009 #1
    1. The problem statement, all variables and given/known data

    The problem asks to graph tangent lines to the given function y = (ln(x)/x, and gives the points (1,0) and (e, 1/e)

    2. Relevant equations

    3. The attempt at a solution

    I got the answer by taking the derivative and finding the slope, and at the point (e,1/e) the equation of the tangent line is y = 1/e, but it also asks to graph the problem and using a ti-89, the only exponential button is e^(x), which requires a "x" value. Any suggestions on how to enter this tangent line on my calculator, I tried y = 1/((1+x)^(1/x)) because the denominator is the definition of "e", but it showed up as a bunch of random lines
  2. jcsd
  3. Jan 23, 2009 #2
    Can you not just use [itex]e^1[/itex] and [itex]\frac{1}{e^1}\equiv{e^{-1}}[/itex] which is e and 1/e?
    Last edited: Jan 23, 2009
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