Question

Evaluate the following:

`cot^-1{cot (-(8pi)/3)}`

Answer 1

We know that

cot^-1 (cot θ) = θ,   (0, π)

We have

`cot^-1{cot  -((8pi)/3)}=cot^-1[-cot((8pi)/3)]`

`=cot^-1[-cot(3pi-pi/3)]`

`=cot^-1(cot  pi/3)`

`=pi/3`