“隐含条件”在高中数学中占有特殊的地位,但不少的学生在解题中常忽视“隐含条件”的存在,因而造成解题的失误。下面举例予以3=5,a=2或-4。当a=2时,A={3,2}成立,但a=-4时,|2a-1|=9 U不成立.∴a=2。二、函数中忽视隐含条件致错例1设全集U={2,3,a2+2a-3},A={|2a-1,|2},CUA={5},, “Implied conditions” occupy a special place in high school mathematics, but many students often neglect the existence of “implied conditions” in solving problems, thus causing mistakes in solving problems. The following example gives 3 = 5, a = 2 or -4. When a = 2, A = {3,2} holds, but when a = -4, | 2a-1 | = 9 U does not hold. Second, ignore the implicit conditions in the function to cause a wrong case Example 1 Let the complete set U = {2,3, a2 + 2a-3}, A = {| 2a-1, | 2}, CUA = {5}