So for finding the magnitude of a vector, velocity for example, we use v=√(v(adsbygoogle = window.adsbygoogle || []).push({}); _{x}^{2}+v_{y}^{2}+v_{z}^{2}), but in special relativity, velocities can not exceed c. Is their a different formula for magnitude in SR, or could a velocity like(in natural units) v=(.9,.9,.9) not exist, since the magnitude comes out to be about 1.5588c, which obviously exceeds c?

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# Vectors in Special Relativity

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