Question

Find the sum of the first 10 terms for the following sequence: a = {-1, 2, 5, ... }

Answer 1

it's +3 each time

Explanation:

the formula for the nth term of an arithmetic progression is

`a _(n) = d * n + a _(1) - d`

Answer 2

see, to find the next number, you need to add three to the last one

for example, the 3 was added to 2, so we have five here

5+3=8

8+3=11

and ....

so the next ten numbers are:

8, 11, 14, 17,20,23,26,29,32,35

I'm sorry, my mother tongue isn't English so please accept my apology if I haven't been able to explain it clearly, it's a pretty easy math problem so I think you got it