a-3-cos-A-B-b-3-cos-B-C-c-3-cos-A-C-

Question Number 212232 by Davidtim last updated on 07/Oct/24

$${a}^{\mathrm{3}} {cos}\left({A}−{B}\right)+{b}^{\mathrm{3}} {cos}\left({B}−{C}\right)+{c}^{\mathrm{3}} {cos}\left({A}−{C}\right)=? \\ $$

Commented by Davidtim last updated on 07/Oct/24

$${I}\:{kindly}\:{request}\:{you}\:{for}\:{helping} \\ $$