已知△ABC,D为AB边上一点,若
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=
.
考点分析:
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圆C关于直线l:x-2y+1=0对称且圆心在x轴上,圆C与y轴相切,则圆C的方程为( )
A.(x-1)
2+y
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B.(x+1)
2+y
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C.
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D.
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(逻辑)下列命题错误的是( )
A.命题“若lgx=0,则x=1”的逆否命题为“若x≠1,则lgx≠0”
B.若p∧q为假命题,则p,q均为假命题
C.命题p:∃x∈R,使得sinx>1,则¬p:∀x∈R,均有sinx≤1
D.“x>2”是“
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为了了解某地区高三学生的身体发育情况,抽查了该地区100名年龄为17.5岁-18岁的男生体重(kg),得到频率分布直方图如图.根据图可得这100名学生中体重在〔56.5,64.5〕的学生人数是( )
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B.30
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(三角求值)已知
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A.
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D.
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若lgx+lgx
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D.2048
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