The Golden Ratio is (sqrt(5)+1)/2, often denoted φ (phi), or about 1.618033988749894848204586834365638117720...

Golden Ratio

Internet references

Mathworld -- Golden Ratio

Related pages in this website

Fibonacci Numbers -- whose successive ratios approach the Golden Ratio

Recurrence Cycle -- A "Golden" Recurrence Relation -- u_n+2 = 1/(u_n u_n+1^φ) has a period of 5.

Trig functions of Special Angles -- The golden ratio pops up here, too.

The webmaster and author of this Math Help site is Graeme McRae.