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Can't finish equation solving step :p area between functions

  1. Mar 7, 2012 #1
    1. The problem statement, all variables and given/known data

    The two functions are x2 and mx, where m is a positive constant. I'm asked to find the value for m where the region enclosed between the two equations in the first quadrant is equal to 8.

    2. Relevant equations


    3. The attempt at a solution

    Since m is a constant, x2 and mx intersect at x = 0 and x = m. So therefore, the area between the equations would be:

    ([itex]\frac{m}{2}[/itex]x2 - [itex]\frac{1}{3}[/itex]x3)|[itex]^{m}_{0}[/itex]

    Which simplifies to:

    [itex]\frac{m}{2}[/itex]m2 - [itex]\frac{1}{3}[/itex]m3

    So clearly all I need to do is set it equal to 8 and solve... however, I'm having major issues actually accomplishing this. I can't see how to get it so I just have m = (constant). Can anyone help? I know the answer I'm trying to get is ~3.63424 but no clue how to get there.
  2. jcsd
  3. Mar 7, 2012 #2
    m^3(1/2 - 1/3)=8
    just get m^3 on one side by multiplying/dividing the equation by some appropriate number?
  4. Mar 7, 2012 #3
    My gosh, I didn't even notice that (m/2)(m^2) simplified to 1/2m^3. I feel so stupid now! Thank you :) I've been trying to solve it keeping the three different powers of m
  5. Mar 7, 2012 #4
    no problem =)
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