Question

Wouldn't this sequence be neither geometric and neither arithmetic?

0.0005, 0.005, 0.05, 0.5

I can'f find a pattern.

And also this sequence, it doesnt look arithmetic or geometric

1/5, 1/4, 1/3, 1/2, 1,...

And also this other question:

The first three terms of the sequence defined by tn = -0.3n + 0.5 are

A. 0.5, 0.8, 1.1
B. -0.3, 0.2, 0.7
C. 0.2, -0.1, -0.4
D. -0.3, -0.8, -1.3

How would you do this, I did something with my calculator and got 0.4, so I just chose C as my answer, but how do you actually figure this out?

Answer 1

The first one is GS , the value of r = 10

the 2nd is neither AS nor GS, but the terms can be described by the formula
term(n) = 1/(6-n)

for the last,
let n=1 to get term(1) = -.3(1) + .5 = 0.2
let n=2 to get term(2) = -.3(2) + .5 = -0.1
etc.
what do you think??

Answer 2

Oh okay this makes sense. Thanks so much. So the third term would equal -0.4, when you plug in the three for the term number.

Answer 3

Y8dn