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楼主 |
发表于 2022-1-19 07:52
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谢谢 creasson大神!解三角方程应该没问题?
譬如:a=5, b=7, c=9
N[Reduce[{S == (5*7 Sin[A] + 5*9 Sin[B] + 7*9 Sin[C])/2, 5/9 == Cos[C]/Cos[A], 7/9 == Cos[B]/Cos[A],
A + B + C == 2 \[Pi], A > 0, B > 0, C > 0, S > 0}, {S, A, B, C}]] // FullSimplify
S == 62.4947 && A == 2.26145 && B == 2.08918 && C == 1.93255
简化一下。
N[Reduce[{S == (5*7 Sin[A] + 5*9 Sin[B] - 7*9 Sin[A + B])/2, 9/Cos[A] == 7/Cos[B] == 5/Cos[A + B],
\[Pi] > A > 0, \[Pi] > B > 0, S > 0}, {S, A, B}], 20] // FullSimplify
S == 62.494682676734509727 && A == 2.2614542282815617331 &&B == 2.0891825389191133599
当然,{5, 7, 9}可以换任意正数数组。 |
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