TCS
Company
Numerical Ability
Sequence and Series
sum of terms 1*2 + 2*2^2 + 3*2^3 4*2^4 +..........+100*2^100 = ?
Read Solution (Total 2)
-
- S = 1*2 + 2*2^2 + 3*2^3 + 4*2^4 .......+ 100*2^100
(-)2*S= 1*2^2 + 2*2^3 + .......+ 99*2^100 + 100*2^101
-------------------------------------------------------
=> S-2S = 2+2^2+2^3+2^4+.........+2^100-100*2^101
=> -S = 2*(2^100-1)/(2-1) - 100*2^101
=> S = 100*2^101 - 2*(2^100-1)
=> S = 100*2^101 - 2^101 + 2
=> S = 99*2^101 + 2 - 9 years agoHelpfull: Yes(24) No(1)
- @rakesh 98*2^101+2.
- 9 years agoHelpfull: Yes(0) No(6)
TCS Other Question