Question

What is the 10th term of the geometric sequence 10,-20,40,

Answer 1

10240

Explanation:

As it is a geometric sequence, you multiply each time with the same number but it is raised to a certain power (1 for the first value, 2 for the second, etc.) Here, we can see the number is -2 as -2x 10 = -20 and 10x
`10 X (-2)^(2) = 40`

We mustcontinue to the tenth value which will be:

`10 X (-2)^(10) = 10 X 2x^(10) = 10240`