Sketch, on separate sets of axes, the graphs of the following, in the interval −180° ≤ θ ≤ 180°. Give the coordinates of points of intersection with the axes, and of maximum and minimum points where appropriate.

a. y = −2 sin θ 

b. y = tan (θ + 180°) 

c. y = cos 4θ 

d y = sin (−θ)