In a geometric sequence, a2=2, a3=16, and a4=128. Which equation can be used to find the nth term of the sequence, an?

an=8⋅2n−1

an=2n−1

an=14⋅8n−1

an=2⋅14n−1

an = 1/4(8)^n-1

Step-by-step explanation:

Given the following in a geometric sequence, a2=2, a3=16, and a4=128.

nth term of a sequence = ar^n-1

a is the first term

r is the common ratio

r = a3/a2 = a4/a3

r = 16/2 = 128/16

r = 8

a2 = ar

2 = 8a

a = 2/8

a = 1/4

The nth term by substituting the parameters will be;

an = 1/4(8)^n-1

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

eventually after a few more steps, your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x