How do you evaluate cot[arccos(-1/2)+arccos(0)+arctan(1/sqrt(3))]?

1 Answer
Jul 4, 2016

1/sqrt 3.

Explanation:

A trigonometric function is the same for any general value. So, only

principal values are considered.

a = arc cos (-1/2). cos a = (-1/2)<0.

a = angle in the 2nd quadrant.. .

So, a = (2pi)/3

b = arc cos 0 = pi/2.

c = arc tan (1/sqrt 3 )= pi/6.

So, the given expression

= cot ( a + b + c ) =cot((2pi)/3+ pi/2+pi/6)

= cot ((4pi)/3) = cot (pi+pi/3)=cot (pi/3)

=1/sqrt 3.

. .