Let f(x)=cot−1x+cosec−1x. then, f(x) is real for
Since , cot−1x exists for all x ϵ R and cosec−1x is real when x≤−1 or x≥ 1, ∴ f(x) is real for x ϵ (−∞,−1)∪(1,∞)
Let f(x)=sec−1x+tan−1x. Then f(x) is real for