What is the common ratio for the sequence 5, -10, 20, -40, ...?
-1/2
2
1/2
-2
-2
To find the common ratio in a sequence, we divide any term in the sequence by its previous term.
Let's apply this to the given sequence:
-10 ÷ 5 = -2
20 ÷ (-10) = -2
-40 ÷ 20 = -2
As we can observe, each term in the sequence is obtained by multiplying the previous term by -2.
Therefore, the common ratio for the sequence 5, -10, 20, -40, ... is -2.