Mathematical Properties of Phi
The Golden Ratio is very interesting in mathematics for multiple reasons, first and foremost because its square and reciprocal have some rather peculiar properties (Tung 7). Note that when we square phi (that is, multiply it by itself), we see that the result is equal to phi plus one:
Also, the reciprocal of phi (1/phi) is equal to phi minus one:
Both of these properties can be deduced from the various definitions of phi found here.