Download the app

Questions  

If sum of the coefficients of the first, second and third terms of the expansion of x2+1xm is 46, 

then the coefficient of the term that does not contain x is

a
84
b
92
c
98
d
106

detailed solution

Correct option is A

Given, mC0+mC1+mC2=46⇒        2m+m(m−1)=90⇒        m2+m−90=0⇒m=9 as m>0 Now, (r+1) thtermof x2+1xm is  mCrx2m−r1xr=mCrx2m−3rFor this to be independent of x put 2m-3r=0⇒r=6.'. Coefficient of the term independent of x is  9C6=84.

Talk to our academic expert!

+91

Are you a Sri Chaitanya student?


Similar Questions

lf the term independent of x in the expansion of 32x213x9is k, then 18k is equal to


phone icon
whats app icon