Question

Find the value of the sum (sigma notation problem)

Answer 1

\[\sum_{i=1}^{n}2i\]

Answer 2

i got into three different equations

Answer 3

sorry i typed the wrong problem

Answer 4

its an arithmetic series

2,4,6,8 .... 2n

use formula for sum of arithmetic series
\[S = \frac{n}{2} (a_1 + a_n)\]

Answer 5

instead of 2i its (i^2+3i+4)

Answer 6

this is what i have so far

Answer 7

hello?