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p3 differentiation watch

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    by taking logarithms, prove that if x=3^(1-t)

    dx/dt= -(ln3)3^(1-t)

    the way ive done it is:

    lnx=(1-t)ln3 .dx
    1/x=-ln3
    1=)-ln3)x
    1=(-ln3)3^(1-t)

    where did the 1 come from?? thanks for your help
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    I'm not too sure what you've done. But:

    lnx = (1-t).ln3 (by taking logs of both sides)

    (1/x)(dx/dt) = -ln3 (implicit differentiation)

    dx/dt = -xln3

    But x = 3(1-t)

    => dx/dt = (-ln3).3(1-t)
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    thanks mokel, i forgot to include the dx/dt bit, otherwise it would have worked.
    cheers
 
 
 
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Updated: May 19, 2005

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