Question

Need help with this question

In picture above

Answer 1

Solution given:

Cos -θ:
`(√(3))/(4)`

since cos -θ=Cos θ

Cos θ :
`(√(3))/(4)`

`(√(b))/(h)`=:
`(√(3))/(4)`

b=
`√(3)`

h=4

p=
`\sqrt{4²-(√(3))²}`=
`√(13)`

So

Sin θ=
`(p)/(h)`=
`(√(13))/(4)`

So third one is a required answer.