急!△ABC中,(a+b+c ) ( a-b+ c ) = 3ac . tanA+ tanC = 3+ 根号3,AB 边上的高为4倍根号3,求A, B,C大...急!△ABC中,(a+b+c ) ( a-b+ c ) = 3ac . tanA+ tanC = 3+ 根号3,AB 边上的高为4倍根号3,求A, B,C大小和a, b,c的长
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![急!△ABC中,(a+b+c ) ( a-b+ c ) = 3ac . tanA+ tanC = 3+ 根号3,AB 边上的高为4倍根号3,求A, B,C大...急!△ABC中,(a+b+c ) ( a-b+ c ) = 3ac . tanA+ tanC = 3+ 根号3,AB 边上的高为4倍根号3,求A, B,C大小和a, b,c的长](/uploads/image/z/10261122-42-2.jpg?t=%E6%80%A5%21%E2%96%B3ABC%E4%B8%AD%2C%28a%2Bb%2Bc+%29+%28+a-b%2B+c+%29+%3D+3ac+.+tanA%2B+tanC+%3D+3%2B+%E6%A0%B9%E5%8F%B73%2CAB+%E8%BE%B9%E4%B8%8A%E7%9A%84%E9%AB%98%E4%B8%BA4%E5%80%8D%E6%A0%B9%E5%8F%B73%2C%E6%B1%82A%2C+B%2CC%E5%A4%A7...%E6%80%A5%21%E2%96%B3ABC%E4%B8%AD%2C%28a%2Bb%2Bc+%29+%28+a-b%2B+c+%29+%3D+3ac+.+tanA%2B+tanC+%3D+3%2B+%E6%A0%B9%E5%8F%B73%2CAB+%E8%BE%B9%E4%B8%8A%E7%9A%84%E9%AB%98%E4%B8%BA4%E5%80%8D%E6%A0%B9%E5%8F%B73%2C%E6%B1%82A%2C+B%2CC%E5%A4%A7%E5%B0%8F%E5%92%8Ca%2C+b%2Cc%E7%9A%84%E9%95%BF)
急!△ABC中,(a+b+c ) ( a-b+ c ) = 3ac . tanA+ tanC = 3+ 根号3,AB 边上的高为4倍根号3,求A, B,C大...急!△ABC中,(a+b+c ) ( a-b+ c ) = 3ac . tanA+ tanC = 3+ 根号3,AB 边上的高为4倍根号3,求A, B,C大小和a, b,c的长
急!△ABC中,(a+b+c ) ( a-b+ c ) = 3ac . tanA+ tanC = 3+ 根号3,AB 边上的高为4倍根号3,求A, B,C大...
急!△ABC中,(a+b+c ) ( a-b+ c ) = 3ac . tanA+ tanC = 3+ 根号3,AB 边上的高为4倍根号3,求A, B,C大小和a, b,c的长
急!△ABC中,(a+b+c ) ( a-b+ c ) = 3ac . tanA+ tanC = 3+ 根号3,AB 边上的高为4倍根号3,求A, B,C大...急!△ABC中,(a+b+c ) ( a-b+ c ) = 3ac . tanA+ tanC = 3+ 根号3,AB 边上的高为4倍根号3,求A, B,C大小和a, b,c的长
(a+b+c)(a-b+c)=a^2+c^2-b^2+2ac=3ac
a^2+c^2-b^2-ac=0,cosB=(a^2+c^2-b^2)/(2ac)=1/2,B=π/3
tanA=1,A=π/4,C=5π/12
A*cosB=4√3,cosB=√3/2,a=8,a/sinA=b/sinB,b=4√6,
sinC=(√6+√2)/4,c=4+4√3
(a+b+c ) ( a-b+ c ) = 3ac展开
可得b^2=a^2 +c^2-ac,根据三角形中 b^2=a^2 +c^2-2ac*cosB
B=60°
所以A+C=120°带入
tanA+ tanC = 3+ 根号3
得tanA=1,-(2+根号3)
A,B,C 45,60,75 75,60,45
∠A=75.∠B=60,∠C=45,b=12倍根号2-4倍根号6,a=8,c=4倍根号3-4,