定理:三角形的外心O、重心G、垂心H依次在同一条直线(欧拉线)上,且
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=
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,其中外心O是三条边的中垂线的交点,重心G是三条边的中线的交点,垂心H是三条高的交点.如图,在△ABC中,AB>AC,AB>BC,M是边BC的中点,AH⊥BC(N是垂足),O是外心,G是重心,H是垂心,OM=1,则根据定理可求得
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的最大值是
.
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定义域为[a,b]的函数y=f(x)图象的两个端点为A、B,M(x,y)是f(x)图象上任意一点,其中x=λa+(1-λ)b∈[a,b],已知向量
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,若不等式
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恒成立,则称函数f(x)在[a,b]上“k阶线性近似”.若函数
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在[1,2]上“k阶线性近似”,则实数k的取值范围为( )
A.[0,+∞)
B.
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C.
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D.
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