What is cot-1(2pi/3)?

1 Answer
Dec 31, 2017

cot^(-1)((2pi)/3) approx 0.445
or
(cot((2pi)/3))^(-1) = -sqrt(3),
depends on the original problem statement.

Explanation:

If this means cot^(-1)((2pi)/3) then it's unusual to evaluate this since generally you find inverse trig functions of ratios, not angles, and (2pi)/3 is an angle. A calculator says that cot^(-1)((2pi)/3) approx 0.445.

If the question actually means (cot((2pi)/3))^(-1) then the problem makes a little more sense.

(cot((2pi)/3))^(-1) = 1/(cot((2pi)/3)) = tan((2pi)/3) = -sqrt(3).