Question

Write a recursive formula for An, the nth term of the sequence 80, -20,5, ....

Answer 1

a[1] = 80; a[n] = -a[n-1]/4

Explanation:

The given sequence has a first term of 80 and a common ratio of -20/80 = -1/4. That is, each term is -1/4 times the previous one. The recursive formula is ...

`A_1=80\\A_(n)=-(1)/(4)* A_(n-1)`