Respuesta :

Answer:

Cos  θ = √3 / 2.

Step-by-step explanation:

The cosine si positive in quadrant IV.

Using the identity cos  θ = √(1 - sin^2 θ):

cos  θ = √(1 - (-1/2)^2)

= √ (3/4)

= √3 / 2

The cosine of theta will be evaluated as:

[tex]cos(\theta) = \dfrac{\sqrt{3}}{2}[/tex]. It can be derived as shown below.

Given that:

sin(θ) = -1/2

Angle θ is in quadrant IV

To find: Value of cos(θ) in simplest form.

Calculations:

For angles belonging to quadrant IV, we have cos and sec trigonometric function evaluating positive result, and all others evaluate negative result on such angles.

Thus, we have:

[tex]sin(\theta) = -1/2\\\theta = arcsin(\dfrac{-1}{2})\\\theta = - arcsin(\dfrac{1}{2})\\\theta = -30^\circ[/tex]

Thus, the cosine can be evaluated as:

[tex]cos(\theta) = cos(-30) = cos(30) = \dfrac{\sqrt{3}}{2}[/tex]

Learn more about trigonometric functions here:

https://brainly.com/question/6904750