Sec 30/2 = - square root of 2

Question

I really need help with passing my trigonometry test please

Answer 1

sec θ = -√2                 The secant is the inverse of the cosine

cos θ = -√2 / 2

 

cos π/4 = √2 / 2           The cosine is negative in QII and QIII

 

θ ∈ {3π/4, 5π/4}