日常生活中我们发现:切香肠时将刀斜着切(即刀面与香肠的轴线所成的角是一个锐角时),会发现截面的边界是一个椭圆.这是为什么呢?能用数学的方法证明吗?怀着对上述问题的好奇,笔者发现这些问题用 In everyday life, we find that when we cut the sausage and cut the knife diagonally (ie, the angle between the knife face and the axis of the sausage is an acute angle), we find that the cross section of the cross is an ellipse. Why? Method to prove it? With the curiosity of the above problems, I found these problems