1
vote
3answers
108 views

Golden ratio / Fibonacci which branch of math?

Friends, The Golden ratio / Fibonacci sequence are studied under which branch of math? Can you recommend some good textbooks on the subject? Thanks
19
votes
2answers
512 views

Approximation for $\pi$

I just stumbled upon $$ \pi \approx \sqrt{ \frac{9}{5} } + \frac{9}{5} = 3.141640786 $$ which is $\delta = 0.0000481330$ different from $\pi$. Although this is a rather crude approximation I ...
7
votes
4answers
688 views

Uses of the 'Golden Ratio'

I have heard much about the numerous appearances of the ratio found in nature: 1.6180339887. Are there any actual mathematical uses that have been found of this number? What are its advantages? Just ...