Trigonometric Functions and Angles

This video tutorial explains how to evaluate trigonometric functions using reference angles. It begins with an introduction to reference angles and the unit circle, highlighting key angles and their coordinates. The tutorial then demonstrates how to evaluate cosine and tangent using reference angles, with examples for cosine of 210° and tangent of -45°. The video emphasizes understanding the signs of trigonometric functions based on the quadrant in which the angle lies.

What is the primary focus of this video tutorial?

• Solving algebraic equations

• Evaluating trigonometric functions using reference angles

• Learning about geometric shapes

• Understanding calculus concepts

What is the radius of the unit circle discussed in the video?

• 2

• 3

• 1

• 0.5

Where does the unit circle intersect the x-axis?

• (1, 1)

• (0, 0)

• (1, 0)

• (0, 1)

What is the angle in radians for 60° on the unit circle?

• pi/2

• pi/4

• pi/3

• pi/6

How is cosine of an angle defined in terms of the unit circle?

• As the y-coordinate

• As the x-coordinate

• As the radius

• As the angle itself

What is the cosine of pi/6?

• 1/2

• sqrt(3)/2

• 1

• 0

What is the reference angle for 210°?

• 60°

• 90°

• 30°

• 45°

In which quadrant is the angle 210° located?

• Quadrant I

• Quadrant II

• Quadrant III

• Quadrant IV

What is the cosine of 210°?

• 1/2

• -1/2

• sqrt(3)/2

• -sqrt(3)/2

What is the cosine of 30°?

• 1/2

• sqrt(3)/2

• 0

• 1