MATHS INVERSE TRIGNOMETRY PRINCIPAL VALUES
For finding the principal value,in this question:
Find the principal value of cot-1(-1/√3)
The answer is cot(π-π/3) which is cot (2π/3)
why is it not just -π/3?
In a similar question, Find the principal value of sin-1(-1/2), I tried doing sin(π+π/6) since sin is negative in 3rd quadrant.But the answer was just -(π/6).Why is there this difference?Someone please explain.Thank You