Question

G(n)=25−49(n−1) complete the recursive formula?

My answer:

g(1)=25

g(n)=g(n-1)+?
What is ?

Answer 1

• g(1) = 25

• g(n) = g(n-1) -49

Explanation:

You can get a clue by filling in n=2 in the explicit formula:

g(2) = 25 -49(2-1) = 25 -49 = g(1) -49

The explicit formula is of the form for an arithmetic sequence:

g(n) = g(1) +d(n-1) . . . . where g(1) is the first term and d is the common difference

Of course, this translates to the recursive formula ...

• g(1) = g(1)

• g(n) = g(n-1) +d

Here you have g(1) = 25, and d = -49. Filling these into the recursive form, you get ...

• g(1) = 25

• g(n) = g(n-1) -49

Answer 2

• g(1) = 25

• g(n) = g(n-1) -49

Explanation:

You can get a clue by filling in n=2 in the explicit formula:

g(2) = 25 -49(2-1) = 25 -49 = g(1) -49

The explicit formula is of the form for an arithmetic sequence:

g(n) = g(1) +d(n-1) . . . . where g(1) is the first term and d is the common difference

Of course, this translates to the recursive formula ...

• g(1) = g(1)

• g(n) = g(n-1) +d

Here you have g(1) = 25, and d = -49. Filling these into the recursive form, you get ...

• g(1) = 25

• g(n) = g(n-1) -49