Question

CHK my answers please! :)
Which is the 6th term in the sequence: a_n= -1/125(5^n-1) ?
-125
-25 <--- my answer
-625
-5

Which is the 10th term in the sequence: -62, -48, -34, -20, -6
78 <--- my answer
50
68
64

Which represents the type of sequence: -99, -96, -92, -87, -81?
Both arithmetic and geometric
Neither arithmetic or geometric
Geometric <--- my answer
Arithmetic

Answer 1

does n start at 0 or at 1?

Answer 2

For which one

Answer 3

for your class work ....

Answer 4

and you might need to clarify the function ... is the 5^(n-1) on top or on bottom?

Answer 5

also, if you give a brief discription of why you think your answers are right, it would help

Answer 6

Ohh I got what u mean now! :) And the n is one the bottom and the (5^n-1) is on the top

Answer 7

For my second questions aren't they all getting subtracted by. 14?

Answer 8

the last 2 seem off to me

Answer 9

added by 14 but yes

Answer 10

-62 + 14(n-1), for n=1,2,3,4,....

n=10 gives us what?

Answer 11

78?

Answer 12

no, work out the grade school addition

-62 + 14(9)

Answer 13

I think 64 is the correct answer?

Answer 14

thats better yes


now the 3rd one ... define geometric and arithmetic for me

Answer 15

They have to have a common difference or common ratio to be geometric or arithmetic I think

Answer 16

geo is ratio, a constant multiplier

add is well, addition, a constant adder

is the 3rd one geo or add ?

Answer 17

I think add but I'm not sure because it doesn't look like it has a common ratio either

Answer 18

if we take the geoMean ... if the sqrt(a1 * a3) = a2 is a good test ... in this case:\[\sqrt{-99(-92)}\ne-96\]
is -96 the arithMean of -99 and -92?

Answer 19

3,4,5,6 not constant either ... so yeah, neither

Answer 20

So it would be geometric because your always multiplying to find the next number in the sequence?

Answer 21

Omg these confuse me so much!

Answer 22

its not geometric since there is no value r such that:

-99r = -96

-96r = -92

Answer 23

Okay it makes a little more sense now.
Thanks for the help. :)