U n f n u n 1 for n 0 displaystyle u_ nvarphi nu_ n-1quad text forquad n0. A n a n-1 5. For a sequence a 1 a 2 a 3.
Given f3 9 fx 3fx 2 4 f9 3f9-2 4 3f7 5 f7 3f7-2 4 3f5 4 f5 3f5-2 4 3f3 4 Substituting f3 9.
Recursion is an example of an iterative procedure. Fx 2 4 which has a seed value of f3 9. Mathematicians start counting at 1 so by convention n1 is the first term. A 2 a 1 5.