Question

If the coefficient of x^2r in the expansion of (x+1/x^2)n-3 is not zero ,then (n-2r/3) is

1) a rational number 2) a positive integer
3) a negative integer
4) a positive rational number ​

Answer 1

Answer:

A positive integer second is a correct option

Answer 2

Step-by-step explanation:

Given = x^2r is the expansion of( x+1/x2)^n-3

we know that r= np-k/p+q

a=1,b=1,p=1,q=2,n=n-3,k=2r

r=(n-3)×1-2r/1+2

r=n-3-2r/3

Here, n-3-2r/3 is in improper fraction . so, change this into mixed fraction

r= n-2r/3-1 is not equal to zero

so, n-2r/3=1

Here r is not equal to zero

By this we can conclude that r=n-2r/3 =1

is a positive integer

hope it is helpful to you

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