If a ≤ tan–1x + cot–1x + sin–1x ≤ b, then
a = 0
b=π2
a=π4
b = π
We have,tan−1x+cot−1x+sin−1x=π2+sin−1x Since −π2≤sin−1x≤π2⇒0≤π2+sin−1x≤π ⇒0≤tan−1x+cot−1x+sin−1x≤π [From (1)]∴a=0 and b=π