2 ;; Please type C-c $ to convert all maxima and latex forms into images.
3 ;; (C) 2004 Yasuaki Honda (yhonda@mac.com)
5 Q: Find the value of a formula {latex \sqrt{\, n + \sqrt{n + \sqrt{n + \cdots}}} latex} for {latex n \in N latex}.
7 A: Let's define x as the value of the given formula:
8 {latex x= \sqrt{\, n + \sqrt{n + \sqrt{n + \cdots}}} latex}.
9 Then x satisfies the formula {maxima x=sqrt(n+x) maxima}&{latex x=\isqrt{x+n} latex}.
10 Remember {maxima x>0 maxima}&{latex x>0 latex}, take square of the formula, we obtain
11 {maxima x^2=x+n maxima}&{latex
12 x^{2}=x+n latex}. The solution of the formula is:
14 {maxima solve(x^2=x+n, x) maxima}&{latex \left[ x=-\ifracn{\isqrt{4\*n+1}-1}{2},\linebreak[0]x=\ifracn{\isqrt{4\*n+1}+1}{2} \right] latex}
16 Since {maxima x>0 maxima}&{latex x>0 latex}, we know that the latter is the answer.
17 {maxima second(solve(x^2=x+n, x)) maxima}&{latex x=\ifracn{\isqrt{4\*n+1}+1}{2} latex}.