Real Analysis proof continuity

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SUMMARY

The function f(x) = x is proven to be continuous at every point p using the epsilon-delta definition of continuity. By letting ε > 0 and setting δ = ε, it is established that for every x in ℝ, if |x - p| < δ, then |f(x) - f(p)| < ε holds true. The discussion confirms that the equality |f(x) - f(p)| = |x - p| is valid, reinforcing the continuity of the function across its domain.

PREREQUISITES
  • Understanding of the epsilon-delta definition of continuity
  • Familiarity with real-valued functions
  • Basic knowledge of limits in calculus
  • Ability to manipulate inequalities
NEXT STEPS
  • Study the epsilon-delta definition of continuity in detail
  • Explore proofs of continuity for other functions, such as f(x) = x²
  • Learn about the implications of continuity in real analysis
  • Investigate the concept of uniform continuity and its differences from standard continuity
USEFUL FOR

Students of real analysis, mathematics educators, and anyone interested in understanding the foundational concepts of continuity in mathematical functions.

kbrono
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Show that the function f(x)=x is continuous at every point p.

Here's what I think but not sure if i can make one assumption.

Let \epsilon>0 and let \delta=\epsilon such that for every x\in\Re |x-p|<\delta=\epsilon. Now x=f(x) and p=f(p) so we have |f(x)-f(p)|<\epsilon.




Or...

can i just say that |x-p| \leq |f(x)-f(p)|<\epsilon. ?


Thanks
 
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kbrono said:
Let \epsilon>0 and let \delta=\epsilon such that for every x\in\Re |x-p|<\delta=\epsilon. Now x=f(x) and p=f(p) so we have |f(x)-f(p)|<\epsilon.

This is correct!
I didn't really understand what your point was in your other idea...
 
and you can say
|f(x)-f(p)| = |x-p| &lt; \delta = \epsilon
 

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