a1=4 , r=3

Question

determine the first five terms and determine common ratio of R 

Answer 1

 

The common ratio is 3 (given), thus we multiply each term by 3 to obtain the next term.

 

a₁ = 4

a₂ = 4(3) = 12

a₃ = 12(3) = 36

a₄ = 36(3) = 108

a₅ = 108(3) = 324

 

 

Answer 2

First term: a₁ = 4

Second term: a₂ = a₁r = 4(3) = 12

Third term: a₃ = a₁r² or just a₂r = = 12(3), etc.   

 

in a Geometric sequence, you simply multiply the most recent term by r to get the next term, over & over.

So the sequence is 4, 12, 36, 108, 324, ...

 

That's easy to remember.  Please comment...was not this topic made clear in your textbook?  If not, please describe your textbook or equivalent classroom material.  Also describe the type of lecture you received on this topic. (This information will help in research that I'm doing.)  Thanks. KS