Question

YOOOO NEED HELP ASAP !!! GIVIN BRAINIEST

Answer 1

Answer:

Correct answer is: f(1) = - 21 ,  f(n) = - 3 · f(n -1)

Step-by-step explanation:

Given geometric sequence:  -21, 63, -189, 567,.........................

Formula for n-th term or a₍ₙ₎ = f(n) = a₁ · q ⁽ⁿ⁻¹⁾  where a₁ is first term and q is quotient (ratio). Formula for (n-1) th term or a₍ₙ₋₁₎ = f(n-1) = a₁ · q ⁽ⁿ⁻²⁾

In this case a₁ = -21 and q = -3

a₍₁₎ = f(1) = -21 · (-3)⁽¹⁻¹⁾ = -21 · (-3)⁰ = -21

f(n) = q¹ · f(n - 1) = q¹ · a₁ q ⁽ⁿ⁻²⁾ = a₁ · q ⁽ⁿ⁻¹⁾ = f(n)

In this case q = -3

f(n) = -3 · f(n -1)

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