Question

How do you evaluate sine, cosine, tangent of `(4pi)/3` without using a calculator?

Answer 1

`- sqrt3/2 ; - 1/2 ; sqrt3`

Explanation:

Use trig table of special arcs and unit circle.
On the unit circle,
`sin ((4pi)/3) = - sin (pi/3) = - sqrt3/2`
`cos ((4pi)/3) = - cos (pi/3) = - 1/2`
`tan ((4pi)/3) = tan (pi/3) = sqrt3`