Geometric Sequences

Is the sequence 2, 4, 12, 48,... geometric?

• yes
• no

What is the common ratio for the sequence:
28, 14, 7, 3.5...

• 2
• 1/2
• -14
• -7

Find the common ratio: 4, -16, 64, -256, ...

• r = -4
• r = 2
• r = -2
• r = 4

Find the common ratio: 64, -16, 4, -1, ...

• r = -8
• r = -1/4
• r = -4
• r = 4

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

• 324, 972, 2916
• 972, 2916, 8748
• 405, 1215, 3645

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

• 36, -108, 324
• -324, -972, -2916
• 324, -972, 2916
• -108, 324, -972

Which formula is used to find the explicit equation for geometric sequences?

• a_n = a_n-1 + d
• a_n = a_n-1 * r
• a_n = a₁ + d(n-1)
• a_n = a₁ * r^n-1

Which formula is used to find the recursive equation for geometric sequences?

• a_n = a_n-1 + d
• a_n = a_n-1 * r
• a_n = a₁ + d(n-1)
• a_n = a₁ * r^n-1

Find the general rule for: 64, -32, 16, -8, …  

• 64(1/2)^n-1
• (-32)^n-1
• 64(-1/2)^n-1
• (32)^n-1

Write an explicit rule for the general term of the sequence 5, 15, 45, . . . ?

• a_n = a_n-1 x 3
• a_n = 5(3)^n-1
• a_n = 3(5)^n-1
• a_n = 5 + (n-1)3