Modulus Inequality Help: Solving |x/2 + 3| > 3-x^2 and |e^x/2 - 3| > 3-e^(2x)

In summary, a modulus inequality involves the absolute value of an expression or variable and states that one absolute value is either less than or greater than another. To solve a modulus inequality, the absolute value must be isolated and both positive and negative cases must be considered. Common mistakes include not considering both cases, simplifying errors, and not checking solutions. A graph can be used to solve a modulus inequality and they have real-life applications in various fields such as physics, finance, engineering, and computer science.
  • #1
truewt
78
0

Homework Statement


Solve [tex] | \frac{x}{2} +3 | > 3-x^2 [/tex]
Hence, solve [tex] | \frac{e^x}{2} -3 | > 3-e^{2x}[/tex]


Homework Equations





The Attempt at a Solution



I've solved the first part. But I have no clue what is the link to the second part?! could there be just typo to the question?? I can't find any links...
 
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  • #2
Let u=e^x

and it becomes

[tex]|\frac{u}{2} +3 | > 3-u^2 [/tex]
 
  • #3
Didn't help.

Anyway I figured the solution already.

should be let [tex]u= - e^x [/tex]
 

1. What is a modulus inequality?

A modulus inequality is an inequality that involves the absolute value of an expression or variable. It states that the absolute value of one expression is either less than or greater than the absolute value of another expression.

2. How do I solve a modulus inequality?

To solve a modulus inequality, you must first isolate the absolute value expression on one side of the inequality. Then, you must consider two cases: when the expression inside the absolute value is positive and when it is negative. Solve for both cases and combine the solutions to find the final solution set.

3. What are the common mistakes when solving a modulus inequality?

The most common mistakes when solving a modulus inequality include forgetting to consider both cases, making errors in simplifying the absolute value expression, and not checking the solutions to make sure they satisfy the original inequality.

4. Can I use a graph to solve a modulus inequality?

Yes, you can use a graph to solve a modulus inequality. Graphing the two expressions on either side of the inequality can help you visualize the solutions and determine which values satisfy the inequality.

5. How are modulus inequalities used in real life?

Modulus inequalities are used in many real-life situations, such as in physics to calculate distances and displacements, in finance to compare absolute values of assets and debts, and in engineering to determine boundary conditions for equations. They are also used in computer science for error correction and cryptography.

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