Relationship between cot and coth
From specialfunctionswiki
Theorem
The following formula holds: $$\cot(z)=i\coth(iz),$$ where $\cot$ denotes the cotangent and $\coth$ denotes the hyperbolic cotangent.
The following formula holds: $$\cot(z)=i\coth(iz),$$ where $\cot$ denotes the cotangent and $\coth$ denotes the hyperbolic cotangent.
