Question

Use each recursive definition to write an explicit formula for the sequence.

a_1=-5, a_n=a_(n-1)-1

Answer 1

can you write down a few of the numbers in the sequence ?
the first number is -5
what is the next number ?

Answer 2

an = -4 + an-1

Answer 3

@cooki3 Is that the formula?

Answer 4

YES

Answer 5

How did you get it?

Answer 6

@phi i don't know how to find the other numbers, do I plug in 2 for n to find the second number in the sequence and so one?

Answer 7

a1=−2,a2=−4a1=−4a2∴an+1=−4an

4an = -4 + an-1

Answer 8

@cooki3 Thank you!! (:

Answer 9

U WELCOME

Answer 10

you have to learn how to interpret this
\[ a_1=-5, \text{ }a_n=a_{n-1}-1 \]

that says a_1 (the first term) is -5
the 2nd equation says: to get the next term, take the "current term" and subtract 1

if we replace n with 2, the 2nd equation says
\[ a_2=a_{2-1}-1 \]
or
\[ a_2=a_{1}-1 \]
you know a1 so you can figure out a2

Answer 11

Oh okay I see, thank you! @phi

Answer 12

so what are the next few #'s in the sequence ?