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討論串[中學] 三角
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△ABC各邊長都有了,角度也算得出來. AE/AD = cos(∠ACB)/cos(∠ABC). 除非AB = AC或者△ABC為直角三角形,. 否則AE/AD =/= sin(∠ABC)/sin(∠ACB) = AC/AB. => (4)錯. 乾脆幫你算好了. 餘弦定理cos(∠ACB) = 13
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內容預覽:
C = cos(theta), S = sin(theta). sin(C)cos(S) < 0. tan(C)cot(S) > 0 => cos(C)sin(S) < 0. -1 < C, S < 1, C S =/= 0. cos(C), cos(S) > 0. => sin(C), sin(S
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