1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

# The sum of 19 terms of the series Sn= 4+10 + 26 + 66 + 162 + 386 + ...... is

A

19*219 + 27

No worries! We‘ve got your back. Try BYJU‘S free classes today!
B

18*219 - 27

No worries! We‘ve got your back. Try BYJU‘S free classes today!
C

18*219 + 27

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D

19*219 - 27

No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

## The correct option is C 18*219 + 27 Sn = 4+10 + 26 + 66 + 162 + 386 + ...... General term = 2 + n2n Let S=38+2∗22+3∗23+4∗24+⋯ ⋯+19∗219−−−−−−−(i) (S2)=19+2∗2+3∗22+⋯ ⋯+19∗218−−−−−−−−(ii) Subtracting (ii) from (i), we get (S2)=19+(2∗2)+19∗219−(22+23+24+25+26+..........+218) =19+(2∗2)+19∗219–(20+21+22+23+24+25+26+..........+218)+3 =19+(2∗2)+19∗219–(219−1)+3 =18∗219+27

Suggest Corrections
0
Join BYJU'S Learning Program
Related Videos
Series
QUANTITATIVE APTITUDE
Watch in App
Explore more
Join BYJU'S Learning Program