Answer:
It's geometric sequence where a_1=12, q=-\dfrac{1}{2}a
1
=12,q=−
2
1
So a_n=12\cdot\left(-\dfrac{1}{2}\right)^{n-1}a
n
=12⋅(−
2
1
)
n−1
Answer:
[tex]a_{n}[/tex] = 12 [tex](-\frac{1}{2}) ^{n-1}[/tex]
Step-by-step explanation:
The nth term of a geometric sequence is
[tex]a_{n}[/tex] = a₁ [tex](r)^{n-1}[/tex]
where a₁ is the first term and r the common ratio
Here a₁ = 12 and r = [tex]\frac{a_{2} }{a_{1} }[/tex] = [tex]\frac{-6}{12}[/tex] = - [tex]\frac{1}{2}[/tex] , then
[tex]a_{n}[/tex] = 12 [tex](-\frac{1}{2}) ^{n-1}[/tex] ← explicit formula
