# 物理 救救孩子吧

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Natural
24天前

hhhhhhh
22天前

21天前

1. Radius of curvature in the x-direction:

$R_x = \frac{a^2}{\sqrt{a^2\sin^2\phi + b^2\cos^2\phi}^3}$

where $a$ is the semi-major axis, $b$ is the semi-minor axis, and $\phi$ is the angle between the x-axis and the plane normal to the surface at the point of interest.

1. Radius of curvature in the y-direction:

$R_y = \frac{ab^2}{\sqrt{a^2\cos^2\phi + b^2\sin^2\phi}^3}$

where $a$ is the semi-major axis, $b$ is the semi-minor axis, and $\phi$ is the angle between the y-axis and the plane normal to the surface at the point of interest.

1. Radius of curvature in the z-direction:

$R_z = \frac{b^2}{\sqrt{a^2\cos^2\phi + b^2\sin^2\phi}^3}$

where $a$ is the semi-major axis, $b$ is the semi-minor axis, and $\phi$ is the angle between the z-axis and the plane normal to the surface at the point of interest.