How to prove that the sequence defined by a1=0, a2=1, an=an−1+an−22 converges to 23?
If we analyse terms:
0,1,12,34,58,⋯.
I'm asked to do this using a previously proved theorem which says that
if you have two sequences bn and cn converging both to the same limit L, then the sequence an defined as b1,c1,b2,c2,b3,… converge to L.
In this case, bn would be 0,12,58,2132,… and cn would be 1,34,1116,4364,…
From here it's seems all I need to do is prove that bn and cn converge to 23 and then, by the theorem, an converges to 23.
I need to define them because I need to prove bn and cn are monotone and bounded, in order to use the monotone convergence theorem. I've got troubles when trying to define bn and cn. Can anyone help me to define them?
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