“普遍性寓于特殊性之中”.在解题中,我们常常发现,图形在特殊位置的有关结论往往带有普遍性,因此,我们应该注意“特殊情形”在解题中的作用. 有些求定值的题,定值并不明确.碰到这类题,同学都感到难以下手.如果学会以“特殊情形”探求出定值是多少,进而进 “Universality resides in particularity.” In the problem-solving, we often find that the relevant conclusions of the figure in a particular position are often universal. Therefore, we should pay attention to the role of “special case” in solving problems. The value of the fixed value question is not clear. When this type of question is encountered, the classmates feel that it is difficult to start. If you learn how to use the “special case” to find the fixed value, go further.