Question

Find an explicit rule for the nth term of the sequence.

-5, -25, -125, -625, ...

Answer 1

can you see the pattern - what value multiplies each term to get the next one?

Answer 2

-5 * x = -25
-25 * x = -125

what is x?

Answer 3

Well it looks like it would be a positive number since it's constant negative

Answer 4

yes

Answer 5

x = 5

Answer 6

thats correct

Answer 7

Here are the options, forgot to post them
an = -5 • 5^n
an = 5 • -5^(n + 1)
an = 5 • -5^n
an = -5 • 5^(n - 1)

Answer 8

this is a geometric sequence with common ratio r = 5
if we represent the first term by a1 then
first term = a1
2nd = a1 r
3rd = a1 r^2
4th = a1 r^3

so nth term = ?

Answer 9

a1r^8

Answer 10

What is nth, 9th?

Answer 11

No thats the 9th term

Answer 12

instead of 3,4,5th term we write n and since the exponent is one less than the n we write the exponent as n-1

Answer 13

when i said 3,4 5th and didnt mean just these - it applies to all terms

Answer 14

Oh okay that makes sense