why is angular displacement considered an axial vector only for small values?
Sakshi, It's because rotations don't add the way vectors are supposed to add. If you had one rotation R1 and followed it with another one: R2, that will give you a different result from rotating R2 and then following that with R1. (Try it.) But if you tried to represent rotations Ri with vectors Ri, the result would be the same in both cases: R1 + R2.
Angular displacement can be many revolutions.
This cannot be represented uniquely by vector, axial or regular.
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