Question

4. Is the sequence 81, 3, 1/9, … arithmetic, geometric, neither, or both? (1 point)
Hint: Remember if there is a common difference between terms then it is arithmetic. If there is a common ratio between terms then it is geometric. If it doesn’t have any of those qualities then it is neither.

o arithmetic
o geometric
o neither

Answer 1

so, you know what is "common ratio" ??

Answer 2

What is an ratio? like an fraction (1/9) ??? the word is familular

Answer 3

yes,
ratio means fraction.

here, fraction with next term as numerator, and current term as denominator.
and its called "common", because its common for all pair of terms.

Answer 4

I put Neither because of 81 but I'm scared if its wrong, and get wrong credit on it i got a D- in math and want to bring it up.

Answer 5

its not neither

Answer 6

Aww pickle juice T_T

Answer 7

let me give you an example:

2,4,8,16,32,....
say this is your sequence.

what do we observe here ?

4/2 =2
8/4 = 2
16/8 =2
32/16 = 2

see the pattern ??
the "ratio" is "common" for all consecutive pair of terms
does this makes sense ?

Answer 8

yes

Answer 9

next one is 64?

Answer 10

correct!

ok, do you see such pattern in the sequence of your question ??

Answer 11

''Common Ratio'' geometric.. O_o

Answer 12

thats correct! :)
your sequence has a common ration, and so its a geometric sequence :)
any doubts ?

Answer 13

ehhh but how its a ''common ratio'' if i don't see a pattern because of the 81 to the 3 how that happen?

Answer 14

divide!

is 3 divided by 81
equals
1/9 divides by 3
???

if yes, then you have a ratio, which is common!

Answer 15

am I doing it right? I got 0.03703703703704…

Answer 16

yeah, but is it same for both ratio ?

Answer 17

pooh :D 1 divided by 9 is 0.1111111… divided by 3 is 0.3703703703704…

Answer 18

thnxxxx

Answer 19

welcome ^_^

Answer 20

Can you Help with another question?

Answer 21

sure

Answer 22

19. During exercise, the recommended maximum heart rate in beats per minute is modeled by the formula, M = 176 – 0.8A, where M is the maximum heart rate and A is the person’s age. Solve the formula for A. At what age would you have a recommended maximum heart rate in beats per minute of 140? (1 point)

Hint: Undo the operations to isolate A just like when we solve equations. Then substitute the 140 in for M.
• 40 years
• 50 years
• 45 years

Answer 23

I was thinking it was 40

Answer 24

A = (176-M)/0.8

Answer 25

A = 36/0.8 = 45 actually

Answer 26

Thank you

Answer 27

welcome ^_^