Cot is the symbol of cotangent trigonometric function in trigonometric function, which was previously written as ctg. Cot coordinate system indicates: cotθ=x/y, cotθ=cosθ/sinθ in trigonometric function, and cotθ= 1/tanθ when θ=kπ, k∈Z (cotθ does not exist when θ = kπ, k∈Z).

Extended data:

Inductive formula:

cot(kπ+α)=cot α

cot(π/2-α)=tan α

cot(π/2+α)=-tan α

Kurt (-α) =-Kurt α

cot(π+α)=cot α

Kurt (π-α) =-Kurt α

References:

Baidu encyclopedia -cot (cotangent function)