Using the index of a series as the domain and the value of the series as the range, is a series a function?

Question

Please explain why it would be i knwo the answer is yes i just need some explanation on why thank you

Answer 1

This is absolutely a function.

For the sequence (a[1] ..... a[n])

S1 = a[1]
S2 = a[1] + a[2]
.
.
.
Sn = a[1] + a[2] + ... + a[n]

A function, by definition, relates each of its inputs to exactly one output. In this case, this function accepts a natural number (1, 2, 3, .... ) and calculates a sum.