Absolute Values and Inequality understanding

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SUMMARY

The discussion centers on the mathematical inequality \(\left | x-c \right |< 1\) and its transformation to \(\left | x \right | \leq \left | c \right | + 1\). Participants clarify that the change from the strict inequality (<) to the non-strict inequality (≤) is valid due to the properties of absolute values and the implications of the symbols used. Specifically, the reasoning hinges on the relationship defined by the triangle inequality and the properties of norms, particularly homogeneity and subadditivity.

PREREQUISITES
  • Understanding of absolute value properties
  • Familiarity with basic inequalities in real analysis
  • Knowledge of triangle inequality
  • Concepts of homogeneity and subadditivity in norms
NEXT STEPS
  • Study the triangle inequality in detail
  • Explore the properties of norms, focusing on homogeneity and subadditivity
  • Practice transforming inequalities involving absolute values
  • Review real analysis textbooks for examples of inequalities
USEFUL FOR

Students of real analysis, mathematicians, and anyone seeking to deepen their understanding of inequalities and absolute values in mathematical contexts.

jzapata87
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Homework Statement



I saw this in my real analysis textbook and I have been trying to understand how this equation \left | x-c \right |&lt; 1

you can get this:\left | x \right |\leq \left | c \right | + 1

Homework Equations



I wanted to know what steps made this possible , particularly why it changed from &lt; to \leq

The Attempt at a Solution


My thinking was that, they did this because it makes no difference as to if you put &lt; or \leq

Any help is appreciated!
Thanks
 
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|x|-|c|\leq |x-c| &lt; 1 \Rightarrow |x|-|c| \leq 1
This one is true because of the symbol \Rightarrow (or as you said, it makes no difference). Things would be different if it were \Leftrightarrow.
 
hikaru1221 said:
|x|-|c|\leq |x-c| &lt; 1 \Rightarrow |x|-|c| \leq 1
This one is true because of the symbol \Rightarrow (or as you said, it makes no difference). Things would be different if it were \Leftrightarrow.

You forgot to tell the young man that to understand this problem he also needs to understand two of the three basic norms Homogeneity and Subadditivity
 

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