x=1+11+11+...⟹x=1+1x⟹x=1±√52
Can the negative solution be considered as a solution? If yes, how is it possible to have a negative solution for a positive continued fraction? If no, how do we prove that it can't be a solution?
Edit 1: I want to understand the assumption we are considering while forming the equation which results in the "extraneous solution".
Answer
No, the negative number is not a solution. You showed that if x is equal to that fraction, then it is either 1+√52 or 1−√52. You calculated possible candidates for solutions, not the solution itself.
You can prove that x must be positive by simply arguing that x is a limit of a sequence with only positive elements, so the limit (if it exists, which should also be proven) must be positive.
No comments:
Post a Comment