CalcRef

Parametric, Polar & Vectors · Polar Coordinates

Polar Arc Length

L=∫αβr2+(drdθ)2 dθL = \int_\alpha^\beta \sqrt{r^2 + \left(\frac{dr}{d\theta}\right)^2}\, d\theta

The arc length of a polar curve r = f(θ) from θ = α to θ = β.

Worked examples

Find the circumference of r = 2 (circle).
  1. dr/dθ = 0. L = ∫₀^(2π) √(4+0) dθ = ∫₀^(2π) 2 dθ = 4π

Answer: 4π

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