Question

4. Write a recursive formula for the sequence 7, 4, 1, –2, –5, .... Then find the next term

Answer 1

4 = 7 - 3

1 = 4 - 3

- 2 = 1 - 3

- 5 = - 2 - 3

This is arithmetic proggresion.

n-th member of A.P is:

an = a1 + ( n - 1 ) d

where a1 is first term , d is common difference

In this case:

a1 = 7 , d = - 3

an = a1 + ( n - 1 ) d

an = 7 + ( n - 1 ) • ( - 3 )

an = 7 - 3 n + 3

an = - 3 n + 10

Next term is a6 so n = 6

an = - 3 n + 10

a6 = - 3 • 6 + 10 = - 18 + 10

a6 = - 8

Answer 2

each term is 3 less than the previous term

Answer 3

a_1 = 7
a_n = a_(n-1) - 3

Answer 4

lol three tutors in one thread....