Question

Express the um using sigma notation:

1 +3/4 +5/9+ 7/16+ 9/25

Answer 1

what, you don't recognize
1,3,5,7,9,...
1,4,9,16,25,...
??
∑ (2k-1)/k^2

Answer 2

maybe
a(1) = 1
a(n+1) = (a(n)+2)/n^2
sum = sigma from n=1 to n = 5 of a(n)

Answer 3

oobleck gave better answer.

Answer 4

Thank you very much :)

Answer 5

What oobleck said, but with the upper and lower limits will give:

n=5
∑ (2k-1)/k^2
n=1