## anonymous one year ago Write the recursive formula for 5, 8, 11, ... an = an-1 + 3 an = an-1 - 3 an = 3an-1 an = an-1 + 1 i dont undderstand the a,n formula at all

1. anonymous

@geerky42

2. anonymous

In your sequence, $$a_1=5$$ is the first term. In the fourth of the given answer choices, for example, you have \begin{align*}a_n=a_{n-1}+1~~\implies~~a_2&=a_{2-1}+1\\&=a_1+1\\&=5+1\\&=6\end{align*} But in your sequence, the second term is $$a_2=8\neq6$$, so it can't be this sequence. Given some term in the sequence, the recursive formula tells you what the next term will be. The value of the next term depends on the previous term.