Answer:
9. a₁ = 13, aₙ = aₙ₋₁ × (-2)
10. aₙ = 2 (-3)ⁿ⁻¹
Step-by-step explanation:
9. aₙ = 13 (-2)ⁿ⁻¹
This is a geometric sequence where the first term is 13 and the common ratio is -2.
So the recursive formula is:
a₁ = 13, aₙ = aₙ₋₁ × (-2)
10. a₁ = 2, aₙ = aₙ₋₁ × (-3)
This is a geometric sequence where the first term is 2 and the common ratio is -3.
So the explicit formula is:
aₙ = 2 (-3)ⁿ⁻¹
