Q179
If 12 + 22 + 32 + . . . . . + p2 = [ p ( p + 1 ) ( 2 p + 1 )6 ] , then 12 + 32 + 52 + . . . . . + 172 is = ?
If 12 + 22 + 32 + . . . . . + p2 = then 12 + 32 + 52 + . . . . . + 172 is = ?
A.
969
AnswerB.
1785
C.
980
D.
1700
Answer: Option A
Solution
Answer: Option A
Solution:
12 + 32 + 52 + . . . . . + 172= (12 + 22 + 32 + 42 + . . . . . + 172) - (22 + 42 + . . . . . + 162)
= (12 + 22 + 32 + 42 + . . . . . + 172) - 22(12 + 22 + . . . . . + 82)
Using given formula