What is the unit circle

The video introduces the concept of a unit circle, emphasizing its basic properties. It explains that a unit circle is a circle with a radius of one unit and highlights the importance of understanding units in a Cartesian coordinate system. The video identifies four key points where the unit circle intersects the x- and y-axes: (1, 0), (0, 1), (-1, 0), and (0, -1). These points are crucial for understanding the unit circle's structure. The video concludes with a brief summary of these concepts, setting the stage for more detailed exploration in future lessons.

What is the radius of a unit circle?

• 3

• 2

• 1

• 0.5

Which of the following is a point where the unit circle intersects the x-axis?

• (0, -1)

• (1, 0)

• (0, 1)

• (-1, 1)

How many key points are there on the unit circle where it crosses the axes?

• 5

• 2

• 3

• 4

What is the y-coordinate of the point where the unit circle intersects the positive y-axis?

• 2

• 0

• 1

• -1

Which of the following is NOT a point on the unit circle?

• (0, 1)

• (0, -1)

• (1, 0)

• (2, 0)