\phiThe Greek letter phi (\phi) is commonly used in mathematics and science to represent various concepts, such as the golden ratio, angles, and phases in wave functions.
Represents the golden ratio, an irrational number approximately equal to 1.6180339887.
\phi = \frac{1 + \sqrt{5}}{2}Euler's formula, which relates complex exponentials to trigonometric functions.
e^{i\phi} = \cos(\phi) + i\sin(\phi)Represents an integral over a full period of a complex exponential function, often used in Fourier analysis.
\int_0^{2\pi} e^{i n \phi} \, d\phi = 0