阿基米德螺线ρ=ρ_0+αθ又称为等速螺线,它的特殊形式是过极点的螺线ρ=αθ。其主要性质有: 1.若点(ρ,θ)在曲线ρ=ρ_0十αθ上,则点(—ρ,—θ)在曲线ρ=—ρ_0+αθ上。这两支曲线关于π/2线对称。特别是(图1)当ρ_0=0时,阿基米德螺线ρ=αθ可以画出关于π/3线的对 The Archimedes spiral ρ=ρ_0+αθ is also called the constant velocity spiral, and its special form is the spiral of the extreme pole ρ=αθ. Its main properties are: 1. If the point (ρ, θ) is on the curve ρ = ρ_0 10 α θ, then the point (-ρ, θ) is on the curve ρ = − ρ 0 + α θ. The two curves are symmetrical about the π/2 line. In particular (Fig. 1) when ρ_0 = 0, the Archimedes spiral ρ = αθ can draw pairs of π/3 lines.