The value of the y-coordinate of point A is -0.5
How to find the y-value?
For a polar point (R, θ), the rectangular coordinates are given by the formulas:
x = R*cos(θ)
y = R*sin(θ)
Here we have the radius R = 1 unit, and the angle is -π/6 radians, then we can find the y-value of point A just as:
y = 1*sin(-π/6)
y = -0.5