Question

Write an equation to describe the sequence below. Use n to represent the position of a term in the sequence, where n = 1 for the first term. -2, 10, -50, ... Write your answer using decimals and integers. 2n-1

Answer 1

In this case, we'll have to carry out several steps to find the solution.

Step 01:

Sequence

-2 , 10 , -50

equation = ?

Step 02:

geometric sequence

r = a2 / a1

a1 = -2

a2 = 10

r = 10 / -2 = -5

an = a1 r ^ (n - 1)

an = (-2 ) * (-5) ^ (n - 1)

The answer is:

an = (-2 ) * (-5) ^ (n - 1)