When both P and Q are true propositions, the proposition P∧Q is true and the rest are false propositions; "∨" means or, which is equivalent to the union of sets. The truth value of the proposition P∨Q is also related to the truth values of P and Q. When both P and Q are false propositions, the proposition P∧Q is false and the rest are true propositions.
Classification of propositions:
① Original proposition: A proposition itself is called the original proposition. For example, if x> 1, then f (x) = (x- 1) 2 monotonically increases.
② Inverse proposition: a new proposition with the opposite conditions and conclusions to the original proposition, such as f (x) = (x- 1) 2 monotonically increasing, then x> 1.
③ No proposition: a new proposition that completely negates the conditions and conclusions of the original proposition, but does not change the order of conditions and conclusions, for example, if X.