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(x+1x)N

If the fifth term in this expansion is independant of X, find the value of N

 Jun 28, 2015

Best Answer 

 #1
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(x+1x)N=xN+NxN1x1+N(N1)2!xN2x2+...

 

The fifth term will therefore contain xN-4x-4 or xN-8.  For this to be independent of x we must have N - 8 = 0 or N = 8

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 Jun 29, 2015
 #1
avatar+33654 
+10
Best Answer

(x+1x)N=xN+NxN1x1+N(N1)2!xN2x2+...

 

The fifth term will therefore contain xN-4x-4 or xN-8.  For this to be independent of x we must have N - 8 = 0 or N = 8

.

Alan Jun 29, 2015

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