Polar Coordinates
Distance from a lighthouse and a compass angle · BC Calculus · greeting
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Lighthouse nav:distance r,compass angle θx = r cos θy = r sin θr² = x² + y²
Owl: Cartesian coordinates ask how far east and how far north. Polar coordinates ask: how far from a lighthouse, and at what compass angle? The pair (r, θ) relocates the same plane with a different grammar. Circles centered at the origin become r = constant. Rays from the origin become θ = constant. Roses and limaçon curves appear as simple formulas in r(θ) that look wild in x and y. We'll convert points, plot basic loci, and face two misconceptions: r must be positive, and θ is always unique. Navigation by radius and angle is flexible — sometimes more than one pair names the same spot.
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