Question

What is the sum of the arithmetic series below?
series in comment .

Answer 1

\[\sum_{i=1}^{15}Fn=4i-1\]

Answer 2

\[Sum=n(\frac{ a1+an }{ 2 })\]


here n=15 and a1=3 and an=59

Answer 3

Where'd 59 come from ?

Answer 4

When you plug in 15 in place of i.