Necessary and sufficient conditions of mathematics in senior two.

Because the negative proposition of a true proposition is not necessarily a true proposition.

P is a sufficient condition for Q, that is, if P is established, then Q is established. This is a true proposition, and its negative proposition is a true proposition, that is, if it is not Q, then it is not P, and it is a sufficient condition for it to be non-P.

Mathematics and geometry in senior two are so abnormal @ ~ @

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The mid-term examination paper of the second volume of mathematics in the second day of junior high school has the answer.

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Mathematical expectation and variance are in urgent need! ! ! But I don't have any points. I still hope you can help me. I appreciate it.

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