Recursive formula — Algebra I · Grade 9 or accelerated Grade 8, what it means and where it is taught
A rule giving an from an-1, plus a starting value.
Taught in Algebra I · Grade 9 or accelerated Grade 8.
Where it is taught
Practise this idea
2 questions in the course bank use Recursive formula, in Sequences, Explicit & Recursive.
Problem 1
Write a recursive formula for 5, 8, 11, 14, ….
Worked answer
a_1 = 5, a_n = a_(n-1) + 3
a1 = 5
an = an-1 + 3
Problem 2
Write a recursive formula for 7, 21, 63, ….
Worked answer
a_1 = 7, a_n = 3a_(n-1)
a1 = 7
an = 3an-1