ANSWER
[tex] \sum _{n = 1} ^{6} 2n[/tex]
EXPLANATION
The series is:
2 + 4 + 6 + 8 + 10 + 12
The first term is:
f(1)=2
The common difference is
[tex]d= 4 - 2 = 2[/tex]
The formula for the corresponding sequence is
[tex]f(n) = 2 + 2(n - 1)[/tex]
[tex]f(n) = 2 + 2n - 2[/tex]
[tex]f(n) = 2n[/tex]
The summation notation is:
[tex] \sum _{n = 1} ^{6} 2n[/tex]
