4 (i), (ii) Finally, we now discuss tan–1 and cot–1
We know that the domain of the tan function (tangent function) is the set
{x : x ∈ R and x ≠ (2n +1) 2
π , n ∈ Z} and the range is R It means that tan function
is not defined for odd multiples of  2
π If we restrict the domain of tangent function to
Fig 2