If we restrict the domain of cotangent function to
(0, π), then it is bijective with and its range as R In fact, cotangent function restricted
to any of the intervals (–π, 0), (0, π), (π, 2π) etc , is bijective and its range is R Thus
cot –1 can be defined as a function whose domain is the R and range as any of the
Rationalised 2023-24
INVERSE TRIGONOMETRIC FUNCTIONS     25
intervals (–π, 0), (0, π), (π, 2π) etc