Answer:
B(-π/3, 1/2), D(7π/6, -√3/2), E(11π/12, -1/2)
Explanation:
You want the coordinates of various points marked on the graph of the sine and cosine functions.
Graph
The horizontal divisions on the graph are multiples of π/6. That is, there are 6 divisions between 0 and π. This means the x coordinates of interest are ...
B = -π/3
D = 7π/6
E = 11π/6
Points B and D lie on the red curve, which the graph tells you is a plot of cos(x). Then the coordinates are ...
B = (-π/3, cos(-π/3)) = (-π/3, 1/2)
D = (7π/6, cos(7π/6) = (7π/6, -√3/2)
Point E lies on the blue curve, which is a plot of sin(x). Its coordinates are ...
E = (11π/6, sin(11π/6)) = (11π/6, -1/2)
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Additional comment
The attachment shows the coordinates of points on the unit circle as (cos(θ), sin(θ)). On the given graph, θ is on the horizontal axis (x), and sine and cosine are on the vertical axis. To make use of the attachment, you find the angle, then look for the (cos, sin) coordinates at that angle.
Negative angles are clockwise from θ=0. To find the corresponding angle on the attachment, add 2π to any negative angle.