If 0 in not in Quadrant I and sec 0 = sqrt 2, find 0 in degrees

Question

If 0 in not in Quadrant I and sec 0 = sqrt 2, find 0 in degrees

Answer 1

secθ = √2, so cosθ = 1/√2

 

cosθ is positive in quadrants 1 and 4

 

Since θ s not in quadrant 1, θ lies in quadrant 4 

 

So, θ = 360° - cos^-1(1/√2) = 360° - 45° = 315°.