Evaluating Cosine and Coterminal Angles

The video tutorial explains how to evaluate trigonometric functions using coterminal angles. It emphasizes the importance of using the smallest positive or negative coterminal angles for sine and cosine evaluations. The tutorial demonstrates how to rewrite angles greater than one revolution by adding 2π, and how to simplify angles using common denominators. It also covers the concept of quadrants and how to determine the coordinates of angles, focusing on the cosine function and its relation to the x-coordinate.

Why is it important to use the smallest positive or negative coterminal angles?

• To simplify calculations

• To make the angle larger

• To ensure the angle is always positive

• To avoid using trigonometric functions

What is the angle being evaluated in the problem?

• Negative 9π over 4

• Negative 8π over 4

• Positive 8π over 4

• Positive 9π over 4

What is the purpose of finding coterminal angles?

• To eliminate the need for trigonometric functions

• To increase the angle's value

• To find an equivalent angle within one revolution

• To change the angle's quadrant

Why is adding 2π preferred over subtracting it for negative angles?

• Subtracting makes the angle positive

• Adding keeps the angle within a smaller range

• Subtracting increases the angle's value

• Adding makes the angle negative

What is the equivalent of 2π in terms of π over 4?

• 2π over 4

• 8π over 4

• 16π over 4

• 4π over 2

Which form of 2π is added to the angle in the problem?

• 8π over 4

• 2π over 4

• 4π over 2

• 16π over 4

What is the simplified coterminal angle equivalent to negative 9π over 4?

• Positive 2π over 4

• Negative π over 4

• Negative 2π over 4

• Positive π over 4

What is the cosine of negative π over 4?

• Negative square root of 2 over 2

• Zero

• One

• Square root of 2 over 2

In which quadrant does negative π over 4 lie?

• First quadrant

• Fourth quadrant

• Third quadrant

• Second quadrant

What happens to the y-coordinate when moving from the first to the fourth quadrant?

• It becomes positive

• It becomes negative

• It remains the same

• It becomes zero