How is the graph of $cot(x)$ valid for negative values of $x$? - Mathematics Stack Exchange
4. Graphs of tan, cot, sec and csc
Trigonometric Functions Cotangent Graph Of A Function Cosecant, PNG, 1087x1024px, Trigonometric Functions, Arcsine, Area, Cosecant, Coseno
Cotangent Function | pi3rcetheheaven5
Since $\tan(25\pi/2)$ is undefined, and $\cot x = \frac{1}{\tan x}$, then why isn't $\cot(25\pi/2)$ undefined instead of $0$? - Mathematics Stack Exchange