KUET_17-18

ABC\triangle \mathrm{ABC} এর বাহুগুলো 3,43, 455 একক হলে, cos2 A+cos2 B+cos2C=\cos ^{2} \mathrm{~A}+\cos ^{2} \mathrm{~B}+\cos ^{2} \mathrm{C}= কত ?

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