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kinlend
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#1
Report Thread starter 16 years ago
#1
Hi, I'm trying to solve a statistical probability problem where the P of an event is based on two variables, x and y such that:

P = x/(x+y) + (50-x)/(100-x-y)

I want to find the values of x and y that give the max P:

or where dP/d(x,y) = 0

How do I do this calculation?

Thanks for any help - much appreciated.
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Juwel
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#2
Report 16 years ago
#2
I know it's an incredibly messy method but from all I know I'd try and get an equation in x or y and substitute...
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username9816
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#3
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#3
(Original post by ZJuwelH)
I know it's an incredibly messy method but from all I know I'd try and get an equation in x or y and substitute...
3D Differentiation?

Right........:confused:
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Juwel
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#4
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As you can tell my knowledge of calculus does not extend to dealing with a third variable. But I can do parametric and implicit differentiation...

I've just had an idea, why not do implicit differentiation?
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GeneralGrievous
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#5
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#5
you have to solve partial dP/dx = 0 and partial dP/dy = 0 simultaneously. (and then do some other stuff to find out if it's a maximum, minimum or saddle point)
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byb3
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#6
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like the post above, search on google for the topic of partial differentiation. You will hopefully find all your answers there.

Adam xx
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