Confusion with the Taylor's Inequality

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SUMMARY

Taylor's Inequality asserts that if |fn+1(x)| ≤ M, then |Rn(x)| ≤ M * |x-a|(n+1) / (n+1)!. The discussion highlights a misunderstanding regarding the conditions under which this inequality holds, particularly the assumption that all derivatives of f are positive, which is not universally applicable. The conclusion drawn is that the inequality is not inherently wrong; rather, the conditions for its application must be clearly understood and correctly interpreted.

PREREQUISITES
  • Understanding of Taylor series and polynomial approximations
  • Familiarity with the concept of remainder terms in calculus
  • Knowledge of limits and continuity in real analysis
  • Basic understanding of derivatives and their properties
NEXT STEPS
  • Study the derivation and applications of Taylor's Theorem
  • Explore the implications of the Mean Value Theorem on Taylor's Inequality
  • Investigate the behavior of higher-order derivatives in Taylor series
  • Learn about counterexamples where Taylor's Inequality does not hold
USEFUL FOR

Students and professionals in mathematics, particularly those studying calculus, real analysis, or numerical methods, will benefit from this discussion. It is also relevant for educators seeking to clarify common misconceptions about Taylor's Inequality.

yupenn
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Taylor's Inequality states:
if |f n+1(x)|<=M
then
|Rn(x)|<=M*|x-a|^(n+1)/(n+1)!
however,
Rn(x)=f n+1(x)*|x-a|^(n+1)/(n+1)!+...
it seems |Rn(x)|>=M*|x-a|^(n+1)/(n+1)! when |f n+1(x)|=M

the inequality is wrong??
 
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You seem to be assuming that all derivatives of f are positive which is NOT generally true.
 

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