The value of the infinitely nested radical
F(m)=m√1+m√1+m√1+m√1+…for integer
m>1 is well-known to be an algebraic number of degree
m. For
m=2, it is the
golden ratio while
m=3 yields the
plastic constant. Define
G(n)=n√1+2n√1+3n√1+4n√1+…For degree
n=2, Ramanujan found that it was simply
3=√1+2√1+3√1+4√1+…More generally
x+1=√1+x√1+(x+1)√1+(x+2)√1+⋯ To see this, note that
x+1=√(x+1)2=√1+x2+2x=√1+x√(x+2)2=√1+x√1+x2+4x+3=√1+x√1+(x+1)√(x+3)2=…However, closed-forms for higher
n such as
G(3)≈1.702219132695458 are not known.
No comments:
Post a Comment