trig unit circles radian

What is the unit circle?

The unit circle is a circle with a radius of 1, centered at the origin (0, 0) of the coordinate plane. It is used in trigonometry to define the sine and cosine functions for all angles.

What is a radian?

A radian is a unit of angular measure used in mathematics. It is defined as the angle created when the radius of a circle is wrapped along the circle's edge. One complete revolution is equal to 2\pi radians.

How are degrees and radians related?

Degrees and radians are both units for measuring angles. One complete rotation is 360 degrees, which is equivalent to 2\pi radians. To convert from degrees to radians, you can use the formula: radians = degrees \times \frac{\pi}{180} .

What are the coordinates of key angles on the unit circle?

On the unit circle, the coordinates of key angles are:

• 0 radians: (1, 0)
• \frac{\pi}{2} radians: (0, 1)
• \pi radians: (-1, 0)
• \frac{3\pi}{2} radians: (0, -1)
• 2\pi radians: (1, 0) again.