Saturday 9 March 2013

Does this property hold true for natural number values of $k$?



While I was playing around with $i$, I discovered an interesting pattern where $i^{2^{-k}}=i^{10^{-k}}$ where $k∈ℕ$.



Here were my steps:
\begin{align}
i^{2^{-k}} & = i^{\frac{1}{2^{k}}} \\
& = i^{\frac{1}{2^{k}}\cdot\frac{5^{k}}{5^{k}}} \\
& = i^{\frac{5^{k}}{10^{k}}} \\
& = i^{10^{-k}} \\

\end{align}



The reasoning behind why I was able to ignore the $5^{k}$ in the numerator is because $i^{5^{k}}$ where $k∈ℕ$ will always be equal to $i$.



I was hoping if someone else could check if I am correct or incorrect for assuming this for all natural number values of $k$.
(I would also like to add I am currently a highschool student that is just curious about math and that curiousity has enabled to come up with different conjectures just for fun.)


Answer



Your conjecture is false:
$$
i^{1/2}\ne i^{1/10}.

$$



The reason for the failure is the fact that the relation $(z^a)^b=z^{ab}$ does not hold for complex numbers.


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