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一元二次不等式恒成立的试题,在各类考卷中屡见不鲜.由于类型较多,许多考生被搞得头昏脑胀,因而对之望而生畏.事实上,这类试题并非考生想象的那么难,完全有规律可循,一旦掌握了其中的要点,解题就会得心应手.这类试题原则上都采用数形结合的思维方法来解答.大致可分为三类.类型一ax~2+bx+c>0(<0,≥0或≤0)在整个实数集上恒成立及其变形.例1 m为何值时,mx~2-mx-1<0恒成立.解:当m=0时,原不等式变为-1<0,符合题意;当m≠0时,只有(?)
One yuan quadratic inequality constant established questions, in all kinds of test papers are not uncommon.As more types, many candidates were confused, and thus daunting.In fact, such questions are not as difficult as the test of the candidates, completely There are rules to follow, once you master the key points, problem-solving will be handy .This types of questions are in principle the use of combination of mathematical methods to answer.General can be divided into three categories. Type ax ~ 2 + bx + c > 0 (<0, ≥0 or ≤0) invariably holds for the entire real number set and its deformation Example 1 When m m is the value of mx ~ 2-mx-1 <0 holds Solution: When m = 0, The original inequalities become -1 <0, in line with the inscription; when m ≠ 0, only (?