Find the value of the following trigonometric functions:

• sin 660°

To find the value of sin 660°, we can simplify the angle first. Since the sine function has a periodicity of 360°, we can subtract 360° from 660°.

Calculating the Angle

Here’s how it works:

• 660° - 360° = 300°

Finding sin 300°

Now, we need to determine the sine of 300°. The angle 300° is in the fourth quadrant, where sine values are negative. The reference angle for 300° is:

• 360° - 300° = 60°

Using the Reference Angle

The sine of 300° is the negative sine of its reference angle:

• sin 300° = -sin 60°

Value of sin 60°

We know that:

• sin 60° = √3/2

Final Calculation

Thus, we can conclude:

• sin 660° = sin 300° = -√3/2

In summary, the value of sin 660° is -√3/2.