Question

Find the common ratio of the geometric sequence: $-1,1,-1,\mathrm{1....}$

• A. $1$
• B. $-1$
• C. $2$
• D. $-2$

Answer 1

The correct option is B $-1$

Given geometric sequence is $-1,1,-1,1,....$

Common ratio $=$ $\frac{\text{second number}}{\text{first number}}$
$=$ $\frac{1}{-1}=-1$
So, the common ratio is $-1$.