Limits: 9-x as x Approaches 4 = 5

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SUMMARY

The limit of the expression 9 - x as x approaches 4 is definitively 5, confirmed by substituting x with 4, resulting in 9 - 4 = 5. However, the discussion highlights the necessity of understanding the epsilon-delta definition of limits for rigorous proof. The user expresses confusion regarding the application of delta and epsilon in this context and seeks clarification on how to determine these values. A recommended resource for mastering this concept is the Khan Academy video on epsilon-delta proofs.

PREREQUISITES
  • Understanding of basic limit concepts in calculus
  • Familiarity with the epsilon-delta definition of limits
  • Knowledge of substitution methods in limit evaluation
  • Basic algebra skills for manipulating expressions
NEXT STEPS
  • Watch the Khan Academy video on epsilon-delta proofs for a comprehensive understanding
  • Practice problems involving epsilon-delta definitions of limits
  • Explore additional resources on limit proofs in calculus textbooks
  • Engage in forum discussions focused on limit concepts for peer support
USEFUL FOR

Students studying calculus, educators teaching limit concepts, and anyone seeking to deepen their understanding of the epsilon-delta definition of limits.

Not An Einstein
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lim(9-x) as x->4 = 5
I thought I was supposed to do this:
9-4=5
5=5
But apparently I was supposed to use delta and epsilon?
I'm not sure how to find either of these. I know you find epsilon first but I'm really confused so if anyone knows just HOW to find it, that would be extremely helpful. Thank you.
 
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