14 含绝对值的不等式解法（14 solution of inequality with absolute value）.docVIP

14 含绝对值的不等式解法（14 solution of inequality with absolute value） Subject: Mathematics Teaching contents: 1.4 with absolute value inequality method Coaching knowledge: 1. to learn the contents of this section, the absolute value of it is the meaning of the definition of absolute value is the key: A = In a, the geometric meaning of the axis: leave the distance from the origin number a. 2. remember x A (a 0) and X (a a 0) solution set type inequalities. X A (a 0) x A or x -a; X a (a 0) -a x a. 3. x, a, or x a (a 0), equivalent to X2, A2, or x2 A2, as a new method to absolute value. 4. in the future to study the related problems, the axis number set of problems can be. Guidance method: Inequality with absolute value, according to the absolute value of the meaning of symbols removed into absolute values, without sign of absolute value inequality (or inequalities). The solution contains more than two commonly used symbol interval absolute value inequality discussion method. Troubleshooting: The example solution about X inequality 2x-1 2m-1 (m, R) If the analytical 2m-1 of 0 or less, which is less than m, 2x-1 2m-1 constant is not established, at this time, the original inequality no solution; If 2m-1 0, m (2m-1) - , 2x-1 2m-1 x M., so 1-m From the available: when m is set, as the solution to the original inequality, when m , the original inequality solution set: {x, 1-m x m}. A typical example of the precision evaluation: 1 cases of inequality 3 = X-2 4 The analytic inequality is equivalent to the original By (1) X-2 = -3, X-2 = 3 or R x = -1, x = 5. or From (2) to -4 X-2 4 R -2 x 6. As shown in the figure, the original set of solutions for inequality {x, -2 x -1 x 6}, or 5 2 cases of inequality 2x-3 = X-1 The analytic classification discussed as follows: When 2x-3 = 0, x = when the original inequality 2x-3 = X-1, x = 2 * x = 2; When 2x-3 0, x , the original inequality - (2x-3) X-1, which is less than x L x. The set of solutions for R inequali