Re: [math-fun] Four solid angles

A + B + C - pi , where A,B,C denote dihedral angles between (normals to) three planes meeting at the common point. WFL On 5/29/15, Henry Baker <hbaker1@pipeline.com> wrote:

BTW, what exactly IS a "solid angle" ?

A 2D angle is acos(A.B), where A,B are unit vectors, and A.B is the dot product.

What is the analogous quaternion formula for a solid angle ?

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