
Re: Noob requests help with recursive formula
Posted:
Mar 14, 2013 7:13 AM


On Mar 13, 1:18 am, Garcia5...@yahoo.fr wrote: > I have two lists, each with 99 elements; A and B. Real numbers. > I want to form a list, C, whose elements are functions (F[]) > of A and B, and also previous elements of C itself. > > C = {F[A1/B1], F[A2/(B2A1/C1)], F[A3/(B3A1/C1A2/C2)], ..., > F[A99/(B99A1/C1 ... A98/C98.)}
...where the integers after A,B,C are element indices.
First define a helper function:
cr[{c_,r_},{a_,b_}] := {#, r+a/#}& @ f[a/(br)]
Then use FoldList. Here is an example with 3 elements:
Rest@FoldList[cr,{0,0},Transpose@ {{a1,a2,a3},{b1,b2,b3}}][[All,1]] //InputForm
{f[a1/b1], f[a2/(b2  a1/f[a1/b1])], f[a3/(b3  a1/f[a1/b1]  a2/f[a2/(b2  a1/f[a1/b1])])]}

