Answer:
2nd and 4th option
Step-by-step explanation:
Answer:
what's thequestion?
Step-by-step explanation:
The n-th term of a geometric sequence with initial value a and common ratio r is given by
.
We have
and
and 
Substitute:

Answer:
Step-by-step explanation:

since we know that
in this expansion is 
thus 
Hope that helps!