Evaluating Trig Functions at Quadrantal Angles

This video tutorial explains how to determine trigonometric function values at quadrantal angles using the unit circle. It covers the sine of 180 degrees, cosine of 0 degrees, and tangent of 3π/2, highlighting the use of the unit circle to find these values. The video also discusses why reference triangles cannot be used for quadrantal angles and explains the undefined nature of tangent at 3π/2.

What can't be drawn for quadrantal angles?

• Tangent lines

• Coordinate axes

• Unit circles

• Reference triangles

Why can't we draw reference triangles for quadrantal angles?

• Reference triangles are not useful for trigonometry

• Because the terminal sides are on the axes

• Due to the unit circle's properties

• Because it's not mathematically possible

What is the radius (R) of the unit circle?

• π

• 2

• 1

• 0

What does the unit circle's radius being 1 imply for trigonometric calculations?

• Simplifies calculations

• Makes calculations impossible

• Complicates calculations

• Has no effect

What is the sine of 180 degrees?

• Undefined

• 0

• 1

• -1

What is the cosine of 0 degrees?

• 0

• 1

• -1

• Undefined

How do you convert 3 PI over 2 radians to degrees?

• 270 degrees

• 180 degrees

• 360 degrees

• 135 degrees

What is the X value at 3 PI over 2 on the unit circle?

• Undefined

• -1

• 0

• 1

What is the Y value at 3 PI over 2 on the unit circle?

• 1

• 0

• -1

• Undefined

What is the tangent of 3 PI over 2?

• 0

• 1

• -1

• Undefined