Which sequence follows the rule an =an–1 + 7?
1 answer:
Answer:
A
Step-by-step explanation:
using the rule : =
+ 7
sequence A with a₁ = 11
a₂ = a₁ + 7 = 11 + 7 = 18
a₃ = a₂ + 7 = 18 + 7 = 25
a₄ = a₃ + 7 = 25 + 7 = 32
sequence A is generated using the rule
sequence B with a₁ = 17
a₂ = a₁ + 7 = 17 + 7 = 24
a₃ = a₂ + 7 = 24 + 7 = 31
a₄ = a₃ + 7 = 31 + 7 = 38
sequence B is not generated using the rule
sequence C with a₁ = - 15
a₂ = - 15 + 7 = - 8
a₃ = a₂ + 7 = - 8 + 7 = - 1
a₄ = a₃ + 7 = - 1 + 7 = 6
sequence C is not generated using the rule
sequence D with a₁ = - 9
a₂ = a₁ + 7 = - 9 + 7 = - 2
a₃ = a₂ + 7 = - 2 + 7 = 5
a₄ = a₃ + 7 = 5 + 7 = 12
sequence D is not generated using the rule
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We can figure this out using the explicit formula.
n represents the term we are looking for.
f(1) represents the first term in the sequence, which in this case, is 7.
d represents the common difference, which in this case, is +3.
f(n) = 7 + 3(n - 1)
f(n) = 7 + 3n - 3
f(n) = 4 + 3n
Now, we can input 214 for n and solve.
f(214) = 4 + 3(214)
f(214) = 4 + 642
f(214) = 646
The 214th term in this sequence is 646.
n represents the term we are looking for.
f(1) represents the first term in the sequence, which in this case, is 7.
d represents the common difference, which in this case, is +3.
f(n) = 7 + 3(n - 1)
f(n) = 7 + 3n - 3
f(n) = 4 + 3n
Now, we can input 214 for n and solve.
f(214) = 4 + 3(214)
f(214) = 4 + 642
f(214) = 646
The 214th term in this sequence is 646.