Arithmetic Sequence?

Question

1. What information about an arithmetic series is need to find its sum?
2. Explain how to use summation notation to express the following series: [2+4+6+8+10+12]
3. In how many different ways can you represent the series [2+4+6+8]?Explain.

Sorry......The question is about Arithmetic Series......

Answer 1

1. You need to know the common difference, the 1st term and the number of terms.

6
E ( 2n) , where E is supposed to be the summation sign.
n=1

As shown above except replace the 6 with a 4.
As 2*E(n) with n=1 below the E and 4 above it. or any equivalent such as 4(1/2 + 1 + 3/2 + 2).