Golden ratio

Golden ratio:

The ratio $\lambda : 1$ where

$\lambda$ is the positive root of the quadratic

$x^2 + x - 1 = 0$

Golden ratio is $\dfrac {\sqrt {5} +1}{2} \, or \dfrac {\sqrt {5} -1}{3 - \sqrt{5}}$

It is the limit of the sequence

$\dfrac{1}{1} , \dfrac{2}{1} , \dfrac{3}{2} , \dfrac{5}{3} \cdots$

The approximate value of the ratio is 1.618.

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