Proof

(related to Corollary: Limit of N-th Roots)

Note that the \(n\)-th roots can be identified with the exponential function of some positive real base \(a > 0\): \[\sqrt[n]a=\exp_a\left(\frac 1n\right).\]

Also note that the sequence \(\left(\frac 1n\right)_{n\in\mathbb N}\) is a convergent real sequence with \(\lim_{n\to\infty}\frac 1n=0\). Because the exponential function of general base is continuous, it follows from the definition of continuity, the definition of the exponential function of general base and the corresponding proposition that

\[\lim_{n\to\infty} \sqrt[n]a=\lim_{n\to\infty} \exp_a\left(\frac 1n\right)=\exp_a(0)=\exp(0\cdot \ln(a))=\exp(0)=1.\]


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References

Bibliography

  1. Forster Otto: "Analysis 1, Differential- und Integralrechnung einer Veränderlichen", Vieweg Studium, 1983