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在高中数学人教必修课本中,推导直棱柱的侧面积公式时,把直棱柱的侧面沿着一条侧棱剪开后展在一个平面上,得到直棱柱的侧面展开图,从而,欲求直棱柱的侧面积,只需求平面展开图的面积,变得直观易求.这种利用侧面展开图,把立体几何问题转化成平面几何问题来解决的方法,我们称之为侧面展开法.该法不但在推导直棱柱、圆柱、圆锥、圆台的侧面积公式时用到,而且在解决立体几何中某些最值问题时,也常常应
In the high school math teaching compulsory textbook, the derivation of the formula of the right prism area, the side of the prism along a side edge cut open in a plane, get the straight prism side development, thus, Of the side area, only need to expand the area of the plane graph becomes more intuitive and easy to seek.This method of using the side expansion diagram, the three-dimensional geometric problems into planar geometry problems to solve, we call the lateral expansion method. Used in the derivation of the formula for the side area of straight prisms, cylinders, cones, and trunks, and it is also frequently used to solve some of the most important problems in solid geometry