Generally speaking, use pure greater than sign? & gt？ , less than this number? & lt？ Connected inequality is called strict inequality, and it is not less than sign (greater than or equal to sign). , not greater than the symbol (less than or equal to the symbol)? Connected inequalities are called non-strict inequalities or generalized inequalities. Generally speaking, using inequality symbols (

Solution of inequality:

(1) One-dimensional quadratic inequality: If the quadratic coefficient of one-dimensional quadratic inequality is less than zero, the same solution is transformed into a quadratic coefficient greater than zero; Note: To discuss:

(2) Absolute inequality: if, then; ;

note:

(1) To solve the problem of absolute value, you can consider removing absolute value. The method of removing absolute value is as follows:

(1) Discuss that the absolute value is greater than, equal to and less than zero, and then remove the absolute value;

(2). Divide the absolute value by squares on both sides; It should be noted that both sides of the inequality sign are non-negative.

(3) Inequalities with multiple absolute values are available? Discuss by zero partition? To solve the problem.

(4) Solving the fractional inequality: transforming the general solution into algebraic expression inequality;

(5) Solution of inequality group: Find the solution set of each inequality in the inequality group, and then find its intersection, which is the solution set of this inequality group. In the intersection, the solution set of each inequality is usually drawn on the same number axis, and their common parts are taken.

(6) Solving inequalities with parameters:

When solving inequalities with parameters, we should first pay attention to whether it is necessary to discuss them in categories. If you encounter the following situations, you generally need to discuss them:

① When two ends of inequality multiply and divide a formula with parameters, we need to discuss the positive, negative and zero properties of this formula.

② When monotonicity of exponential function and logarithmic function is needed in solving, their bases need to be discussed.

(3) When solving a quadratic inequality with letters, we need to consider the opening direction of the corresponding quadratic function, the conditions of the roots of the quadratic equation with one variable (sometimes we need to analyze △), compare the sizes of two roots, and let the roots be (or more) but contain parameters, all of which should be discussed.