If θ=sin−1x+cos−1x−tan−1x≥0, then the smallest interval in which θ lies, is given by
π2≤θ≤3π4
−π4≤θ≤0
0≤θ≤π4
π4≤θ≤π2
We have, θ=sin−1x+cos−1x−tan−1x=π2−tan−1x=cot−1xSince, 0≤x≤1, therefore π4≤θ≤π2