The video tutorial explains how to solve cosine problems using the unit circle and periodicity. It begins by introducing the problem and the concept of the unit circle, breaking it into thirds. The tutorial then demonstrates how to simplify cosine expressions by factoring out 2π, and evaluates cosine values using this method. It also covers calculating cosine through reflection about the y-axis. The video concludes by summarizing the method of factoring out 2π to simplify calculations.

What is the main focus of the problem discussed in the video?

• Evaluating cosine using the unit circle

• Evaluating sine using the unit circle

• Finding the area of a circle

• Calculating tangent using the unit circle

How does the unit circle help in evaluating trigonometric functions?

• By dividing the circle into equal parts

• By measuring the circumference

• By calculating the area of a circle

• By providing a visual representation of angles

How is the unit circle divided to simplify the problem?

• Into eighths

• Into halves

• Into quarters

• Into thirds

What is the equivalent of 2π in terms of thirds?

• 4π/3

• 5π/3

• 7π/3

• 6π/3

What is the purpose of dividing the unit circle into thirds?

• To complicate the problem

• To simplify calculations

• To measure the radius

• To find the diameter

Why can 2π be disregarded in the calculation?

• It represents a full circle, returning to the same point

• It is an imaginary number

• It is less than 1

• It is not relevant to cosine

What is the remainder when simplifying 8π/3?

• π/3

• 2π/3

• 4π/3

• 3π/3

What is the cosine of 2π/3?

• √3/2

• 1/2

• -1/2

• -√3/2

What does the reflection about the y-axis imply for cosine?

• Cosine becomes positive

• Cosine becomes negative

• Cosine becomes zero

• Cosine remains unchanged

What is the x-value of the point for cosine at 2π/3?

• -√3/2

• √3/2

• 1/2

• -1/2