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    • Thread Starter

    Can someone explain what this really is about because from what I have learnt in 2 hours is that u just manipulate the variables to find the rate of something that is increasing or decreasing but I don't get what the point is .

    Name:  1483747035629-1937288554.jpg
Views: 22
Size:  364.8 KB for this question I don't get how the answer is just -kM . Why wouldn't you do something like this Attachment 609096609098

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    • Community Assistant

    Community Assistant
    dm/dt is proportional to -M, the minus there as it is a rate of decrease, so it is equal to some multiple of M.

    dm/dt = -kM
    • TSR Support Team

    TSR Support Team
    You're overcomplicating it. All this question is asking you to do is to express the problem described in the question using an equation. The question says that the rate of loss of mass of the leaf is proportional to the mass of the leaf. The rate of change of mass of the leaf is \frac{dM}{dt} and since this is proportional to the mass of the leaf, \frac{dM}{dt}=kM. However, since we are talking about the rate of loss of mass of the leaf, the rate of change of the mass of the leaf is negative. So \frac{dM}{dt}=-kM (assuming k>0).
    • Community Assistant
    • Study Helper

    Community Assistant
    Study Helper
    (Original post by coconut64)
    Attachment 609096609098

    It's not clear what you're trying to show in this image. Can you please explain it line by line?
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Updated: January 7, 2017
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