Gamma angle

284
0
For two arbitrary vectors, subtending an angle, [tex] \gamma [/tex], I know the cos relationship, but what's the sin relationship ? I ask because there is an ambiguity by only knowing the cosine form, since vector A can be either above or below vector B.

[tex] cos\gamma = cos\theta_1 cos\theta_2 + sin\theta_1 sin\theta_2 cos( \phi_1 - \phi_2 ) [/tex]

I don't know what's the correct term I should type in for search engine.
 

mathman

Science Advisor
7,583
351
For two arbitrary vectors, subtending an angle, [tex] \gamma [/tex], I know the cos relationship, but what's the sin relationship ? I ask because there is an ambiguity by only knowing the cosine form, since vector A can be either above or below vector B.

[tex] cos\gamma = cos\theta_1 cos\theta_2 + sin\theta_1 sin\theta_2 cos( \phi_1 - \phi_2 ) [/tex]

I don't know what's the correct term I should type in for search engine.
It would clarify things if you could state what all these angles are and their relationships.
 

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