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March 25th, 2011, 07:41 AM   #1
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find the sum

find the sum of this sequence
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March 25th, 2011, 08:23 AM   #2
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Re: find the sum



Start by differentiating both sides.
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March 25th, 2011, 10:14 AM   #3
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Re: find the sum

Quote:
Originally Posted by aswoods


Start by differentiating both sides.
i dont get u
what does diffirentiation has to do with my sequence?
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March 25th, 2011, 10:42 AM   #4
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Re: find the sum

ok i get it now
thanks buddy
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March 25th, 2011, 12:24 PM   #5
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Re: find the sum

Using aswoods' helpful suggestion:

(1)

Differentiating both sides:

(2)

Subtract (1) from (2):



Combine right-side with common denominator and simplify:



Multiply through by 2:

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March 25th, 2011, 05:57 PM   #6
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Re: find the sum

Hello, islam!

This can be solved algebraically.


Quote:



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March 25th, 2011, 10:58 PM   #7
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Re: find the sum

Don't forget the case x=1...
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March 25th, 2011, 11:52 PM   #8
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Re: find the sum

Quote:
Originally Posted by aswoods
Don't forget the case x=1...
n(n + 1)
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March 26th, 2011, 01:24 AM   #9
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Re: find the sum

thank u aswoods ,markfl, soroban,chaz
i am really grateful for ur help
u all r really creative i wish u all
great breakthroughs in math,
wealth and happiness.
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