Answer:
A1 = 4
A2 = 7
A3 = 10
A4 = 13
A5 = 16
Step-by-step explanation:
To solve this, and know the arithmetic series, all you need to do is solve the value of k; now to know the value of k, the expression here is giving you a clue of the possible values.
First the symbol ∑ means summation, and that means that you need to sum all the terms in the expression that goes from one value to another, and which are the values? below the symbol, indicates the first value you need to take, in this case, the part where it says k = 1, means that the first value of k you need to put into that expression is 1. The value above the symbol, the part where it says 5, means that this is the final value that you have to put into the expression, so, this means that to get A2, A3 and A4, you need to put the values of k from 1 to 5.
Now that we know this, let's solve for k with the values from 1 to 5:
A1 = 1 + 3(1) = 1 + 3 = 4
A2 = 1 + 3(2) = 1 + 6 = 7
A3 = 1 + 3(3) = 1 + 9 = 10
A4 = 1 + 3(4) = 1 + 12 = 13
A5 = 1 + 3(5) = 1 + 15 = 16
