Question

Use the unit circle to determine the sine, cosine, and tangent of the angle a=-3π/6.

Answer 1

The first choice is correct.

Step-by-step explanation

We want to use the unit circle to determine the sine, cosine and tangent of the angle,

`\alpha = - (3\pi)/(6)`

This simplifies to

`\alpha = - (\pi)/(2)`

This is a quadrantal angle. This angle intercepts the unit circle at, (0,-1).

We know that on the unit circle, the x-coordinate is given by;

`x = \cos( \alpha )`

Hence

`\cos( \alpha ) = 0`

and the y-coordinate is given by;

`y = \sin( \alpha )`

This implies that

`\sin( \alpha ) = - 1`

The tangent is

The correct choice is A.