Question

Find the first five terms of the geometric sequence for which a1 = 10 and r = –1

Answer 1

A geometric sequence works like this: you have a starting point $a_1$, and you generate the next term by multiplying the previous one by the common ratio $r$

In your case, the common ratio is -1, which means that you get every other term by changing the sign of the previous one.

So, the sequence goes like this:

$10,\ -10,\ 10,\ -10,\ldots$