Lighthouse Beam Along Shoreline
Author: Jamie Mulholland
Date: October 28, 2007

A lighthouse is located on a small island 3 km away from the nearest point on a straight shorline and its light makes four revolutions per minute.  How fast is the beam of light moving along the shoreline when it is 1 km from P?

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LightHouse = (0, -3)
t = 0 (slider from 0 to 1, step 0.01)
P = (0, 0)
c = Circle(LightHouse, 1.0)
C: (-sin(2.0 * 3.14 * t), cos(2.0 * 3.14 * t) + y(LightHouse))
beam = Ray(LightHouse, C)
θ = Angle(C, LightHouse, P)
Shore = Segment((-5.0, 0.0), (5.0, 0.0))
B = Intersect(beam, Shore)
b = Segment(P, B)
d = Segment(P, LightHouse)
Ocean, a, e, f, g = Polygon((-5.068752474942087, 0.01145874582368167), (4.931247525057913, 0.01145874582368167), (4.931247525057913, -4.988541254176319), (-5.068752474942087, -4.988541254176319))