Hi, I'm trying to derive the Frenet Serret Formulas, but I am having trouble to understand why, after some checking, that the derivative of binormal vector is:(adsbygoogle = window.adsbygoogle || []).push({});

[itex]\frac{d\hat{b}}{ds}=-\tau\hat{n}[/itex]

I understand that, [itex]\hat{t}\wedge\frac{d\hat{n}}{ds}\parallel\hat{n}[/itex] and [itex]|\frac{d\hat{b}}{ds}|=\tau[/itex], but why the negative sign? Isn't it equally possible that it has a positve sign?

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# I Frenet Serret Formulas

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