Respuesta :
Answer:
First term = 9.
Common ratio = 2.
Step-by-step explanation:
A geometric sequence has a common ratio r.
If the first term is a:
10th term = ar^9 and 5th term is ar^4
so 1th term / 5th term = r^5
So 4608/144 = r^5
r^5 = 32
so r = 2.
Substituting for r in the 5th term:
a(2)^4 = 144
a = 144 / 16
a = 9.
Answer:
first term:9
common ratio: 2
Step-by-step explanation:
aₙ = a₁*rⁿ⁻¹
a₅ = a₁*r⁵⁻¹ = a₁*r⁴ = 144 ... (1)
a₁₀ = a₁*r¹⁰⁻¹ = a₁*r⁹ = 4608 ... (2)
(2)÷(1) r⁵ = 32
r = 2
a₁ = 144 / 2⁴ = 9
