数学上有一类“等周问题”:在周长相等的平面图形中,什么样形状面积最大?在讨论这个问题之前,请你动手做一个简单的实验,将一条长度一定的柔软细丝的两端连接起来,围成任意形状的封闭曲线,将此曲线轻轻地搁置在一个蒙有肥皂膜的铁框内,曲线的表面立即蒙上一层肥皂膜.如果用小针将 In mathematics, there is a class of “isochronic problems”: What is the largest area of ​​shape in a planar graphic with the same perimeter? Before discussing this question, please do a simple experiment and put a piece of soft filament of a certain length. The ends are connected together to form a closed curve of any shape. The curve is gently placed in a metal box with a soapy film. The surface of the curve is immediately covered with a layer of soap. If you use a small needle,