Let A, B and C be the interior angles of a triangle S.
(a). Prove that cos^2 A + cos^2 B + cos^2 C = 1 - 2 cosA cosB cos C.
(b). If cos^2 A + cos^2 B + cos^2 C =1, which type of triangle does S belong to?
M2 trigo question
2010-07-10 7:01 am
回答 (2)
2010-07-10 7:35 am
✔ 最佳答案
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2010-07-10 13:26:33 補充：
(b)Right-angled triangle
2010-07-10 8:19 am
Missing Part b) ?
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