spherical coordinates

…When a Cartesian coordinate system is given in space, the foot of the perpendicular line drawn from point P in space to the xy plane is Q, the length of the line segment OP is r , the angle that half line OQ makes with the positive direction of the x- axis is θ, and the angle that half line OP makes with the positive direction of the z -axis is φ, then the position of point P is expressed as ( r , θ, φ) (Figure 8). ( r , θ, φ) are called the polar coordinates or spherical coordinates of P. The relationship between this and P's Cartesian coordinates ( x , y , z ) is given by x = r sinφcosθ, y = r sinφsinθ, z = r cosφ. …

*Some terminology explanations that mention "spherical coordinates" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…空間に直交座標系が与えられたとき，空間の点Pからxy平面へ下ろした垂線の足をQとして，線分OPの長さをr，半直線OQがx軸の正の向きとなす角をθ，半直線OPがz軸の正の向きとなす角をφとすれば，点Pの位置は(r，θ，φ)で表される(図8)。(r，θ，φ)をPの極座標または球座標spherical coordinatesという。これとPの直交座標(x,y,z)との関係はx＝rsinφcosθ,y＝rsinφsinθ,z＝rcosφで与えられる。…

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出典｜株式会社平凡社世界大百科事典 第２版について | 情報