滿意答案: tanA=sinA/ cos A tanA=1/cotA (sinA)^2+( cos A)^2=1 正弦定理 a/sinA=b/sinB=c/sinC 餘弦定理 a^2=b^2+c^2-2bc*cosA b^2=c^2+a^2-2ac*cosB c^2=a^2+b^2-2ab*cosC (1)二倍角公式: (a)sin2a ...
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