\tau
The Greek letter \tau (tau) is commonly used in mathematics and science to represent various concepts, such as the time constant in physics, the golden ratio conjugate, or a specific type of function in mathematics. It is a versatile symbol that appears in different contexts depending on the field of study.
Tau as the golden ratio conjugate
\tau = \frac{1}{\phi} = \frac{2}{1 + \sqrt{5}}
Tau as the time constant in an exponential decay function
V(t) = V_0 e^{-t/\tau}
Tau as the divisor function in number theory
\tau(n) = \sum_{d|n} d