I'm doing some work with vectors, and essentially, I have two vectors: a large vector and a unit vector pointing in a different direction. I would like to decompose the large vector into the components that are in the direction of and perpendicular to the unit vector.(adsbygoogle = window.adsbygoogle || []).push({});

This is in three dimensions, and shouldn't be too hard using cos and acos. However, this is for some computer work, where cos and acos are expensive -- is there any better way to do this using purely vector math (such as cross product, etc) or some other method not quite so expensive?

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# Vector decomposition

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