1问题1的引入经常打篮球的学生提出一个问题:篮球停止在地面上的时候,太阳光斜照下来,篮球的阴影部分是否是一个椭圆呢?对此可用立体几何、解析几何的原理进行探讨.解法1画图分析,如图1,假设球的半径为R,地面为平面γ,光线与地面所成的角为α,过球心且垂直于光线的平面为φ,它 1 The introduction of Question 1 The students who often play basketball raise a question: When the basketball stops on the ground, the sunlight shines, whether the shadow part of the basketball is an ellipse? This can be discussed by the principles of solid geometry and analytic geometry Solution 1 Drawing analysis, as shown in Figure 1, assuming that the radius of the ball is R, the ground is plane γ, the angle between the light and the ground is α, and the plane perpendicular to the light ray is