二次根式的难点之一是求式子a~2~(1/2)的值,尽管课本中有字母一般表示正数的说明,但由于两个正数相减未必是一个正数,所以计算形如((a-b)~2)~(1/2)的值时,往往错误颇多。如果能熟悉它的各种不同形式的解法,那就能从本质上加深a~2~(1/2)=│a│的理解。 One of the difficulties of secondary roots is the value of equations a~2~(1/2), although the letters in the textbook usually indicate the positive numbers, but because the two positive numbers are not necessarily a positive number, so When calculating the value of ((ab)~2)~(1/2), there are often many mistakes. If you can become familiar with its various forms of solution, you can essentially deepen the understanding of a~2~(1/2)=|a|.