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Homework Help: Derivatives-volume of a cyclinder

  1. Mar 11, 2010 #1
    1. The problem statement, all variables and given/known data
    im just reviewing for a test tomorrow and im stuck on this question, any help is appreciated

    if the volume of a cylinder is v=50-3pir^3, the surface area is 100cm^2 and the range of the radius is 0<r<3, what is the radius that will give the maximal volume?

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Mar 12, 2010 #2


    Staff: Mentor

    I don't think you're giving us all the information. Can we assume that this is a circular cylinder? And that formula for the volume is very unusual - it gives negative values for volume when r is greater than about 1.744 cm.

    Are you sure you have given us the exact information of this problem?
  4. Mar 12, 2010 #3
    im so sorry, i was using the wrong equation for the volume, is should be v=50r-pir^3, now the question is really easy but thanks for taking your time to help
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