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解不等式
由此求解 。
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完整解法
3[0]
1. Rearrange the inequality to have zero on one side and combine the terms into a single algebraic fraction.
2. Expand and simplify the numerator.
3. Identify the critical values by setting the numerator and denominator to zero.
Numerator:
Denominator:
4. Use a sign test to determine the intervals satisfying the inequality.
The critical values in ascending order are , , and (since ).
Testing the sign of in each interval:
- (e.g., ):
- (e.g., ):
- (e.g., ):
- (e.g., ):
The fraction must be . The roots of the numerator are included, but the root of the denominator () must be excluded to avoid division by zero.
Thus, or .
3[1]
1. Solve the inequality from part [0] to establish the foundation for substitution.
Finding the critical values, we set the numerator and denominator to zero:
Analysing the signs of the expression across these intervals gives the solution for part [0]:
2. Substitute $x$ with $|x|$ to relate the target inequality to the previous part.
Since , the target inequality is algebraically identical to the one in part [0] but with replacing :
Substituting into the solution from part [0]:
3. Solve the first inequality involving the modulus.
For the range , we note that is naturally true for all real values of . Thus, we only need to solve :
4. Solve the second inequality involving the modulus and combine the valid ranges.
For the range , expanding the modulus condition gives:
Combining all the separate valid ranges of gives the final continuous solution set.
or or
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