Geometric Compound Problems

Write the explicit formula for the geometric sequence.

• a_n = 162(2/3)^n-1

• a_n = (2/3)(162)^n-1

• a_n = 162(3/2)^n-1

• a_n = 162 + (n-1)(-54)

The rule for finding a_n of a geometric sequence is

a_n = 10(2)^n-1.

What is the common ratio (r) of the sequence?

• 2

• 2ⁿ

• 10

• 20

A geometric sequence has a common ratio (r) of 3 and the 8th term (a₈) is 13,122.

What is the first term of the sequence (a₁)?

• 18

• 6

• 2

• 3

What is the common ratio of the geometric sequence whose first term is 5 and third term in 245?

• 7

• 49

• 120

• 240

Which formula is a recursive equation for geometric sequences?

• f(n) = f(n-1) + d, f(1) = __

• f(n) = f(n-1) * r, f(1) = __

• f(n) = f(1) + d(n-1)

• f(n) = f(1) * r^n-1

Determine whether the sequence is arithmetic, geometric, or neither.

• arithmetic

• geometric

• neither

Write the explicit formula for the geometric sequence.

• a_n = 4(3)^n-1

• a_n = 3(4)^n-1

• a_n = -4(3)^n-1

• a_n = 3(-4)^n-1

Find the next three terms: 4, 12, 36, 108, ...

• 324, 972, 2916

• 972, 2916, 8748

• 405, 1215, 3645

Find the next three terms: 3, -18, 108, -648

• -6480, -3880, -233280

• 6480, -38880, 233280

• 5184, -31104, 186624

• 3888, -23328, 139968

Find the common ratio: -3, -9, -27, -81, ...

• CR = 6

• CR = -6

• CR = 3

• CR = -3