4d Example 1 (Evaluate Trig Functions using intercepts of the unit circle)

The video tutorial explains how to evaluate the sine, cosine, and tangent of angles at 90 and -90 degrees using the unit circle. It highlights the limitations of using right triangles for these angles and emphasizes the importance of the unit circle's coordinate points. The tutorial also discusses reflections and how they affect trigonometric evaluations on the axes.

Why can't we use right triangles to evaluate trigonometric functions at 90 degrees?

• Because the hypotenuse is undefined

• Because there are no adjacent or opposite sides

• Because the angle is too large

• Because the unit circle is not applicable

What is the sine of 90 degrees on the unit circle?

• 1

• -1

• 0

• Undefined

What is the cosine of 90 degrees on the unit circle?

• 1

• 0

• Undefined

• -1

What happens to the tangent of an angle when the denominator is zero?

• It becomes one

• It becomes zero

• It becomes undefined

• It becomes negative

What is the sine of -90 degrees on the unit circle?

• -1

• 1

• Undefined

• 0