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Calculus Help

  1. Dec 1, 2004 #1
    I am having trouble with these two problems, I was wondering if anyone here could help me.

    1. Given a sphere of radius 10 inches. Calculate the altitude of the inscribed right circular cylinder of maximum volume.

    2. A man 6 feet tall walks away from a light 30 feet high at the rate of 3 miles per hour. How fast is the further end of his shadow moving, and how fast is his shadow lengthening?
  2. jcsd
  3. Dec 1, 2004 #2
    this really belongs in the calculus forum.

    for the first problem, you can simplify it by looking at only the section of a circle in the first quadrant of the coordinate plane. then look to maximize the area of a rectangle inscribed within the area of the 1/4 circle.

    the second problem reminds me that I haven't done a related rates problem in some 6 months, and don't feel like brushing up at the moment :-)
  4. Dec 1, 2004 #3


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    these are pythagoras and similar triangles problems.
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