Q27 of 51 Page 18

Mark the correct alternative in the following :

If the coefficients of the term and the term in the expansion of are equal, then the value of n is


Given:




For nth term ; k=n-1


So for (n+1)th term ; k= n


& for (n+3)th term ; k =n+2


Coefficients for the above terms are equal;




(20-n)(19-n) = (n+2)(n+1)


380-39n+n2 = n2+3n+2


42n-378=0


n=9

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