Evaluate for sine cosine and tangent using reference angles

The video tutorial explains how to evaluate the sine, cosine, and tangent of a negative angle, specifically -25π/4. It covers finding coterminal angles by adding 2π until a positive angle is achieved, and then determining the reference angle. The tutorial emphasizes the importance of using the smallest positive coterminal angle to find the reference angle, which shares the same coordinate points as π/4. Finally, it demonstrates how to evaluate the trigonometric functions using these reference angles, considering the signs of the coordinates in the 4th quadrant.

What is the purpose of finding a coterminal angle when dealing with negative angles?

• To convert the angle into degrees

• To find an equivalent positive angle

• To simplify the angle to zero

• To change the angle's quadrant

How do you determine the reference angle for an angle in the fourth quadrant?

• By subtracting the angle from π

• By adding the angle to 2π

• By subtracting the angle from 2π

• By dividing the angle by 2

Why is it important to use the smallest positive coterminal angle when finding the reference angle?

• To avoid negative values

• To make calculations easier

• To ensure the reference angle is acute

• To match the original angle

In the fourth quadrant, what is the sign of the sine function?

• Zero

• Undefined

• Negative

• Positive

What is the value of the tangent function for the angle -, 25π / 4?

• Undefined

• 0

• 1

• -1