Evaluate the inverse trig function within a composition

The video tutorial guides students through evaluating the tan inverse of negative sqrt(3)/3. It begins with identifying the coordinate point that corresponds to this value, followed by determining the related angle on the unit circle. The tutorial emphasizes the constraints of tangent functions and calculates the cosine of the angle. Finally, it offers tips for solving similar problems, highlighting the importance of understanding coordinate points and angle relationships.

What is the cosine of the angle -π/6?

In which quadrant is the cosine positive for the angle -π/6?