Question

Select all the correct answers.

Answer 1

• The measure of reference angle is
  `30^(\circ)`.
• 
  `\cos \theta=(√(3))/(2)`

Explanation:

Converting
`\theta` to degrees,

`\theta=\left((11\pi)/(6) \right) \left((180)/(\pi) \right)=330^(\circ)`

This means
`\theta` lies in Quadrant 4, and thus its reference angle is
`360^(\circ)-330^(\circ)=\boxed{30^(\circ)}`

Since
`\theta` lies in the fourth quadrant,
`\sin \theta` and
`\tan \theta` are negative.

Since
`\theta` lies in the fourth quadrant,
`\cos \theta` is positive, and is equal to
`\cos (30^(\circ))=\boxed{(√(3))/(2)}`