Question

Evaluate r=5

∑(r+1)2
r=1​

Answer 1

`\sum (r+1)^2 = 90`

Explanation:

Given

`\sum (r+1)^2; r = 1,2....5`

Required

Evaluate

`\sum (r+1)^2; r = 1,2....5` is equivalent to :

`(1 + 1)^2 +(2 + 1)^2 +(3 + 1)^2 +(4 + 1)^2 +(5 + 1)^2`

`(2)^2 +(3)^2 +(4)^2 +(5)^2 +(6)^2`

`4 + 9 + 16 + 25 + 36`

`90`

Hence:

`\sum (r+1)^2 = 90`