Sequences

-21, -16, -11, -6, ...

Is this sequence arithmetic, geometric, or neither?

• arithmetic (common difference d = 5)

• geometric (common ratio r = 5)

• neither (no common difference OR common ratio) neither (no common difference OR common ratio)

Write the explicit formula for the sequence shown below.

3, -3, -9, -15

• a_n=3+6(n-1)

• a_n=3−6(n-1)

• a_n=6−3(n-1)

• a_n=6+3(n-1)

An arithmetic sequence is described by the function f(n)=−3n+7. What are the first 5 terms of the sequence?

• 7, 10, 13, 16, 19

• 4, 1, -2, -5, -8

• -4, -1, 2, 5, 8

• -7, -10, -13, -16, -19

What do we call this sequence: 6,18,54,162,…

• Arithmetic Sequence

• Geometric Sequence

• Fibonacci Sequence

• Triangular Sequence

Find the first four terms of the sequence given the rule:
a_n = 4(5)^n-1

• 20, 100, 500, 2500
• 5, 20, 80, 320
• 4, 20, 100, 500
• 4, 9, 14, 19

Given the recursive formula, find the first four terms:
a_n = a_n-1 + 5
a₁ = -16

• -16, -21, -26, -31
• 5, -11, -27, -43
• -16, -80, -500, -200
• -16, -11, -6, -1

Write the recursive formula for 6, 17, 28, 39, 50....

• a_n=a_n-1+11
  a₁=6
• a_n=a_n-1-4
  a₁=6
• a_n=a_n-1+9
  a₁=6
• a_n=a_n-1+6
  a₁=6

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 of the following recursive formulas represents the given sequence.

7, 14, 28, 56, 112, ...

• $a_1=7$ , $a_n=a_{\left(n-1\right)}+7$

• $a_1=7$ , $a_n=a_{\left(n-1\right)}\cdot7$

• $a_1=7$ , $a_n=a_{\left(n-1\right)}\cdot2$

• $a_1=7$ , $a_n=a_{\left(n-1\right)}+14$

Identify the common ratio for the given geometric sequence.

48, 12, 3, 0.75, ...

• r = 4

• r = -36

• r = $\frac{1}{4}$

• r = 3