What is the recursive formula for this geometric sequence?
4, -12, 36, -108, ...

Answer: C.
Step-by-step explanation:
The first number is a positive 4, which is your a1. Then the geometric sequence goes to a negative implying that it is multiplied by a negative. So the a1 = 4 and it is being multiplied by a negative 3.
Answer: C
[tex]\left \{ {{a_{1}=4 } \atop {a_{n}=a_{n-1}*(-3) }} \right.[/tex]
Step-by-step explanation:
The starting amount (a1) = 4
The rate is -3 because 4 * -3 = 12 and -12 and -12 * -3 = 36 etc.