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若样本1+x1,1+x2,1+x3,…..1+xn,的平均数为10,方差为2,则...
若样本1+x1,1+x2,1+x3,…..1+xn,的平均数为10,方差为2,则对于样本2+x1,2+x2,2+x3,…..2+xn,,其平均数和方差的和为 .
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动点P为椭圆
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上异于椭圆顶点(±a,0)的一点,F
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椭圆
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的四个顶点A,B,C,D构成的四边形为菱形,若菱形ABCD的内切圆恰好过焦点,则椭圆的离心率是( )
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B.
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C.
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D.
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已知双曲线中心在原点且一个焦点为F(
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-
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=1
B.
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-
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D.
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-
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=1
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设定点M(3,
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)与抛物线y
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)
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)
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