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could someone help me with this simple problem. As always with homework, hints are specially welcome.

Let $v=(v_1,v_2)$ be a two-dimensional unit vector with complex coefficients. If $|v_1|<a$ and $|v_2|<a$ then $|v_1|+|v_2|\geq \frac{1}{a}$.

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up vote 2 down vote accepted

I think I got it.

\begin{equation} |v_1|+|v_2|\geq \frac{|v_1|}{a}|v_1|+\frac{|v_2|}{a}|v_2|\geq \frac{|v_1|^2+|v_2|^2}{a}=\frac{1}{a} \end{equation}

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Very nicely done. – copper.hat Jul 17 '12 at 18:11

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