Spiral - Helix

Japanese: 螺旋(螺線) - らせん

(1) Also known as a spiral. A plane curve expressed in polar coordinates as r = f(θ) (f is a monotonic continuous function). Examples include the Archimedes spiral expressed as r = aθ (a is a positive constant), the logarithmic spiral with r = ke(a/)θ, and the hyperbolic spiral with r = a/θ. (2) Also known as a helix. A space curve contained on the side of a right circular cylinder that intersects with the generating line of the cylinder at a constant angle is called a normal spiral. With t as a parameter, it is expressed as x = acos t, y = asin t, and z = bt (a and b are constants).

Source : Heibonsha Encyclopedia About MyPedia Information

Japanese:

（１）渦巻線とも。極座標でr＝f（θ）（fは単調連続関数）と表される平面曲線。r＝aθ（aは正の定数）で表されるアルキメデスの螺線，r＝ke(a/)θの対数螺線，r＝a/θの双曲螺線等がある。（２）つるまき線とも。直円柱の側面に含まれる空間曲線で円柱の母線と一定角度で交わるものを常螺旋という。tを媒介変数としてx＝acos t，y＝asin t，z＝bt（a，bは定数）で表される。

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