Greetings,(adsbygoogle = window.adsbygoogle || []).push({});

I wonder if a proof of the relation between the directional cosines of two vectors and cosine between two vectors is available? In order to clarify what I meant I put a screen shot fromVector and Tensor Analysisby Hay.

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Relations Involving the Directional Cosines

**Physics Forums | Science Articles, Homework Help, Discussion**