<Li> Magnetic flux in physics </Li> <Li> The golden ratio 1 + 5 2 ≈ (\ displaystyle (\ tfrac (1 + (\ sqrt (5))) (2)) \ approx) 7000161803398874989 ♠ 1.618 033 988 749 894 848 204 586 834...in mathematics, art, and architecture . </Li> <Li> Euler's totient function φ (n) in number theory; also called Euler's phi function . </Li> <Li> The cyclotomic polynomial functions Φ (x) of algebra . </Li>

What is the value of phi in mathematics