Question

How do you find the sum of `3+5i` from i=1 to 20?

Answer 1

1110

Explanation:

`S_n= n/2(a_1+a_n)`

`a_1= 3+5(1)= 8`

`a_20= 3+5(20)= 103`

To find the sum, since there are 20 terms:
`S_20= 20/2(8+103)`
`S_20= 20/2(8+103)=1110`