Sin theta=-1/2 then cos theta=

Step-by-step explanation:

Step one:

Applying the SOH CAH TOA principle

assuming all dimensions are in cm

Step two:

Given data

opposite= 1 cm

hypotenuse= 2 cm

Sin(θ)= opp/hyp

Sin(θ)= 1/2

Sin(θ)= 0.5

θ= sin-1 0.5

θ= 30°

hence  from tables cos 30°= 0.866

Ф= 111.06° = 0,617π rad

Step-by-step explanation:

sec(Ф) = 1/cos(Ф)

1/cos(Ф) = -2.782

cos (Ф) = -0.3594

Ф= arcos (-0.3594)

Ф = 111.06° * (π/180) = 0,617π radians.