The sum 1+ 12 (12+22 )+ 13 (12+22+32 )+ upto 10 terms is equal to :
- 130
- 155
- 3152
- 3252
Answer
(3) 3152
Solution
General term: Tn= 1n (12+22+ +n2 )
Tn= 1n n(n+1)(2n+1)6= 2n2+3n+16
S10= 16 [2 n=110n2+3 n=110n+10 ]
S10= 16 [2(385)+3(55)+10 ]
S10= 9456= 3152
Answer: (3)