6.4 Remediation

Select all of the following that are geometric sequences

• 2, 4, 8, 16, ...

• 5, 10, 15, 20, ...

• 625, 125, 25, 5, ...

• 0.5, 1, 1.5, 2, ...

Match each geometric sequence with its explicit or recursive formulas. 

• a_n = 2 (a_n-1); a₁= 2

• 2,4,8,16,…

• a_n=3(2)^n-1

• 3,6,12,24,…

• a_n=1/3(a_n-1); a₁=81

• 81,27,9,3,…

• a_n=625(1/5)^n-1

• 625,125,25,5,…

Choose the correct explicit formula to model the geometric sequence in the table. 

A population of bacteria is tripling every hour.  If the population size is 1000 bacteria after the 1^st hour, which recursive formula models the function?

A population of bacteria is tripling every hour.  If the population size is 1000 bacteria after the 1^st hour, which explicit formula models the function?

A population of bacteria is tripling every hour.  If the population size is 1000 bacteria after the 1^st hour, how many will there be after 8 hours?

• 1500000
• 3000000
• 2187000
• 1000000