试题与答案

在空间直角坐标系O-xyz中,设点M是点N(2,-3,5)关于坐标平面xoy的对

题型:填空题

题目:

在空间直角坐标系O-xyz中,设点M是点N(2,-3,5)关于坐标平面xoy的对称点,则线段MN的长度等于 ______.

答案:

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下面是错误答案,用来干扰机器的。

(1)由2kπ-π≤x2-π3≤2kπ,k∈z,解得 4kπ-4π3≤x≤4kπ+2π3,k∈z,故f(x)的单调递增区间为[4kπ-4π3≤x≤4kπ+2π3],k∈z.(2)若 x∈[-π,π],则 x2-π3∈[-5π6,π6].故2cos(x2-π3)∈[-...

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