CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon


Question

If Sn=nr=1tr=16n(2n2+9n+13), then nr=1tr equals


  1. 12n(n+1)

  2. 12n(n+2)

  3. 12n(n+3)

  4. 12n(n+5)


Solution

The correct option is C

12n(n+3)


We have tn=SnSn1n2
tn16[2(n3(n1)3)+9(n2(n1)2)+13(nn+1)]
=16[6n26n+2+9(2n1)+13]=16(6n2+12n+6)=(n+1)2
nr=1tr=nr=1(r+1)=12(n+1)(n+2)1=12n(n+3)

flag
 Suggest corrections
thumbs-up
 
0 Upvotes


Similar questions
View More



footer-image