I am not sure how sigma notation works, can somebody explain how to solve this? It isn't the second choice.

first answer is correct

Step-by-step explanation:

Hello, we want to write 2 + 4 + 6 + ... + 20

for n = 1, 2n = 2*1 =2

for n = 2, 2n = 2*2=4

for n = 3, 2n=2*3=6

etc

so

thanks

answer: group b.

step-by-step explanation:

d no solution

step-by-step explanation: