Download the app

Questions  

The sum of the series r=0n(1)r  nCr12r+3r22r+7r23r+15r24r++m terms  is 

 

a
2mn−12mn2n−1
b
2mn−12n−1
c
2mn+12n+1
d
None of these

detailed solution

Correct option is A

∑nn (−1)rnCr12r+3r22r+7r23r+… upto m terms =∑r=0n (−1)r nCr⋅12r+∑r=0n (−1)r⋅nCr3r22r+∑r=0n (−1)rnCr7r23r+…=1−12n+1−34n+1−78n+…up to M terms=12n+122n+123n… upto m terms =12n1−12nm1−12n=2mn−12mn2n−1

Talk to our academic expert!

+91

Are you a Sri Chaitanya student?


Similar Questions

If the coefficients of  P th, ( p + 1)th and (p + 2)th terms in the expansion of (1 + x)n are in AP, then


phone icon
whats app icon