Trigonometric Functions and Reference Angles

The video tutorial explains the concept of reference angles and their significance in trigonometry. It covers how to calculate reference angles for both degree and radian measures and demonstrates their application in evaluating trigonometric functions like cosine and sine. The tutorial emphasizes the importance of determining the correct sign based on the quadrant of the original angle and provides tips for effectively using reference angles in computations.

What is the primary purpose of learning about reference angles?

• To memorize angle values

• To simplify the calculation of trigonometric functions

• To compute angles in different units

• To understand the history of trigonometry

In which quadrant does the angle 150 degrees lie?

• Third quadrant

• First quadrant

• Fourth quadrant

• Second quadrant

How do you calculate the reference angle for 150 degrees?

• Subtract 150 from 360

• Add 150 to 90

• Subtract 150 from 180

• Multiply 150 by 2

Which trigonometric function is positive in the second quadrant?

• Cosine

• Secant

• Sine

• Tangent

What is the cosine of 150 degrees using its reference angle?

• -1/2

• 1/2

• -Square root of 3 over 2

• Square root of 3 over 2

What is the sine of 150 degrees using its reference angle?

• -1/2

• Square root of 3 over 2

• -Square root of 3 over 2

• 1/2

What is the reference angle for 5π/4?

• π/6

• π/4

• π/3

• π/2

In which quadrant does the angle 5π/4 lie?

• Fourth quadrant

• Third quadrant

• Second quadrant

• First quadrant

What is the cosine of 5π/4 using its reference angle?

• -Square root of 2 over 2

• Square root of 2 over 2

• -1/2

• 1/2

What is the sine of 5π/4 using its reference angle?

• -Square root of 2 over 2

• Square root of 2 over 2

• -1/2

• 1/2