Mathematics, 22.07.2021 08:50 bbygrill
Chứng minh rằng nếu $A \setminus B=A$ thì $A\cap B=\emptyset$.
Giải: Giả sử $A\cap B\neq \emptyset \Rightarrow \exists x \in A \cap B$. Suy ra $x \in B \, ^{(1)}$ và $x \in A \, ^{(2)}$. Từ $(1)$ suy ra $x \notin A \setminus B$. Mà $A \setminus B=A$ nên $x \notin A$ (mâu thuẫn với (2)).
Phương pháp chứng minh nào đã được sử dụng?
Select one:
a. Gián tiếp
b. Trực tiếp
c. Tầm thường
d. Phản chứng
Answers: 3
Mathematics, 21.06.2019 17:00
For which of the following counts would a binomial probability model not be reasonable? a)the number of people in a classroom born in januaryb) the number of people in a classroom with red hair c) the number of people admitted to a hospital in a day with a particular disease d) the number of heart beats in a one-minute perio.
Answers: 3
Mathematics, 21.06.2019 19:40
The cross-sectional areas of a right triangular prism and a right cylinder are congruent. the right triangular prism has a height of 6 units, and the right cylinder has a height of 6 units. which conclusion can be made from the given information? the volume of the triangular prism is half the volume of the cylinder. the volume of the triangular prism is twice the volume of the cylinder. the volume of the triangular prism is equal to the volume of the cylinder. the volume of the triangular prism is not equal to the volume of the cylinder.
Answers: 1
Mathematics, 21.06.2019 22:00
Determine which postulate or theorem can be used to prove that lmn =nmo
Answers: 3
Chứng minh rằng nếu $A \setminus B=A$ thì $A\cap B=\emptyset$.
Giải: Giả sử $A\cap B\neq \emptyset...
English, 05.11.2019 08:31
Mathematics, 05.11.2019 08:31
Social Studies, 05.11.2019 08:31
Mathematics, 05.11.2019 08:31
Mathematics, 05.11.2019 08:31
English, 05.11.2019 08:31
Physics, 05.11.2019 08:31
Mathematics, 05.11.2019 08:31
History, 05.11.2019 08:31
Mathematics, 05.11.2019 08:31
Mathematics, 05.11.2019 08:31