所谓“虚设法”是在分析和解决物理问题时,人们假设与想象出某些物理量或物理过程,然后将虚设问题与实际问题进行对比分析,确认其具有等效性.“虚设法”的可取之处在于帮助我们将一个复杂问题分为几个虚拟的简单问题,从而使一些表面上无法人手的繁杂问题由死变活,由繁变简.以下举例说明. The so-called “virtual search” is to analyze and solve physical problems. People assume and imagine certain physical quantities or physical processes, and then compare and analyze the virtual problems with actual problems, and confirm that they have equivalence. The desirable aspect of " is that it helps us to divide a complex problem into several simple virtual problems, so that some seemingly unwieldy problems can be changed from death to death. The following examples illustrate.