Question

What is the exact value of `sec (2pi/3)`?

Answer 1

`sec ((2pi)/3) = 1/cos ((2pi)/3)`

On the trig unit circle:

`cos ((2pi)/3) = cos (pi - pi/3) = - cos( pi/3) = -1/2` (trig table)

`sec ((2pi)/3) = -2`