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#1 2009-11-20 02:19:20

BeachRum1962
Member
Registered: 2009-11-20
Posts: 3

Tough equation to differentiate

I am trying to differentiate the following equation:

B(t) = B*/(1+be^-at)  that is be raised to -at.  a & b are parameters.  The correct answer is as follows:

dB(t)/dt = aB(t)[1-(B(t)/B*)]

Please help, I have been working hours using chain rule product rule, substituting, etc. but to no avail. Thanks.

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#2 2009-11-20 03:46:21

soroban
Member
Registered: 2007-03-09
Posts: 452

Re: Tough equation to differentiate


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#3 2009-11-20 03:56:17

simplyjasper
Member
Registered: 2009-11-15
Posts: 24

Re: Tough equation to differentiate

I did mine through partial fractions and manage to get the result smile...
You can try mine if you think you are more comfortable with partial fractions...

Solving For Partial Fractions, u will get

Using B(t):

Taking Common Factor:

Last edited by simplyjasper (2009-11-20 04:45:20)

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#4 2009-11-20 04:01:50

BeachRum1962
Member
Registered: 2009-11-20
Posts: 3

Re: Tough equation to differentiate

Many thanks and impressive work. Take that nap now wink

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#5 2009-11-20 04:22:14

BeachRum1962
Member
Registered: 2009-11-20
Posts: 3

Re: Tough equation to differentiate

Ok simplyjasper please post your method but I almost had it using soroban's method.

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#6 2009-11-20 04:45:55

simplyjasper
Member
Registered: 2009-11-15
Posts: 24

Re: Tough equation to differentiate

BeachRum1962 wrote:

Ok simplyjasper please post your method but I almost had it using soroban's method.

Posted by editing my previous post smile

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