In a geometric sequence, the 5th term is 9 and the 7th term is 36. Use the geometric mean to find the 6th term.

18

Step-by-step explanation:

you need to get from 9 to 36 in 2 steps by multiplying, so you need to find what gets 9 to 26 in one turn. 9*4=36, and because 4 is square we know you can multiply by 2 twice to get the same effect. 9*2=18. and just to make sure we can check that 18*2=36

answer:

step-by-step explanation:

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for