Answer:
The common difference d is d = -3
The recursive formula is: [tex]\mathbf{a_n=a_{n-1}-3}[/tex]
Step-by-step explanation:
We need to find the common difference and the recursive formula.
a. 22, 19, 16, 13, …
First we will find common difference
The formula of arithmetic sequence is: [tex]a_n=a_1+(n-1)d[/tex]
where a_n is nth term, a_1 is 1st term and d is the difference
Looking at the sequence we get: a_1=22, a_2=19
Using these values we can find d, the common difference
[tex]a_n=a_1+(n-1)d\\put\:n=2, a_2=19, a_1=22\\19=22+(2-1)d\\19=22+d\\d=19-22\\d=-3[/tex]
So, the common difference d is d = -3
Now, we will find the recursive formula:
The recursive formula is of type: [tex]a_n=a_{n-1}+d[/tex]
We have found common difference d = -3
So, the recursive formula will be:
[tex]a_n=a_{n-1}+d\\a_n=a_{n-1}+(-3)\\a_n=a_{n-1}-3[/tex]
The recursive formula is: [tex]\mathbf{a_n=a_{n-1}-3}[/tex]
