From the recursive formula:
[tex]a_n=a_{n-1}-\pi[/tex]
we notice that the common difference of the sequence is -pi. Now we know that the first term is 7, then the explicit formula is:
[tex]a_n=7-\pi(n-1)[/tex]
when
[tex]n>0[/tex]
We can relabel this sequence if we assume we start at zero, in this case the sequence will be:
[tex]a_n=7-\pi n[/tex]
when:
[tex]n\ge0[/tex]
