Question

What is the sum of the arithmetic series `sum_(i=1)^8(-2+2i)`?

Answer 1

`sum_(i=1)^8 (-2+2 i) = 56`

Explanation:

`1` st term is `a= -2+2*1= 0`

`2` nd term is `a_2=-2+2*2= 2 :. d=2-0=2 , n=8`

Sum of Arithmetic seris is `S= n/2{2 a+(n-1)d}`

`:.S =8/2(0 + 7*2)= 4 * 14 =56`

`sum_(i=1)^8 (-2+2 i) = 56` [Ans]