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DE MORGAN’S LAW ON UNION

In this article we learn the de morgan’s theorem statement and its proof in set theory and our main focus in on the de morgan’s law on union we will study the statement of de morgan’s law on union and its proof by venn diagram and also will we do some example so that it will clear better and solve some question based on de morgan’s law on union.

They are named after Augustus De Morgan , a British mathematician in the 19th century. The set of all those elements which are either in A or in B is the union of two sets A and B.

In other we can say that the complement of union of two sets is intersection of their complement.we can also call in de morgan’s laws on the union. The mathematical representation of de morgan’s laws on union is:

(A∪B)’=A’∩B’

Further in this article we will do the proof of this law by venn diagram as well as by written.

And also take some questions related to this topic to understand this more easily and fast.

STATEMENT OF DE MORGAN’S LAW THEOREM IN SET THEORY

Let two sets be A and B and their complements  be A’ And B’ .

First law of De morgan’s says that the union of complement of the two sets A and B is equal to the intersection of their separate complements.

(A∪B)’=A’∩B’

Second law of De morgan’s  says that the complement of the intersection of two sets A and B is equal to the union of their separate complements.

(A∩B)’ = A’ B’

DE MORGAN’S LAW PROOF IN SET THEORY

FIRST LAW OF DE MORGAN’S LAW:

DE MORGAN’S LAW ON UNION IN SET THEORY

This Is also known as the first law of de Morgan’s theorem which says that the union of complement of the two sets A and B is equal to the intersection of their separate complements.

(A∪B)’=A’∩B’

PROOF OF DE MORGAN’S LAW ON UNION BY VENN DIAGRAM

PROVING (A∪B)’=A’∩B’

  • (A∪B)’

Therefore (A∪B)’=A’∩B’

EXAMPLE OF DE MORGAN’S LAW ON UNION

Example 1 :- Let the universal set  U={2,3,4,5,12,13,17}

       The two subset A={12,13,17}

                                   B={2,3}

       (A∪B)= {2,3,12,13,17}

        (A∪B)’={4,5}

        A’ = {2,3,4,5}

        B’ = {4,5,12,13,17}

        A’B’={4,5}

Therefore (A∪B)’=A’∩B’

Example 2 :- Let the universal set  U={1,2,4,5,6,7}

       The two subset A={5,6,7}

                                   B={1,2}

       (A∪B)= {1,2,5,6,7}

        (A∪B)’={4}

        A’ = {1,2,4}

        B’ = {4,5,6,7}

        A’B’={4}

Therefore (A∪B)’=A’∩B’

CONCLUSION

In this article we learn the de morgan’s theorem statement and its proof in set theory and  our main focus in on the de morgan’s law on union we talk about the statement of 

de morgan’s law on union  and its proof by venn diagram and also  do some examples so that it will clear better and solve some questions based on de morgan’s law on union.

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Get answers to the most common queries related to the IIT JEE Examination Preparation.

Find n(X ∪ Y). If X and Y are two sets such that n(X) = 19, n(Y) = 37 and n(X ∩ Y) = 12?

Ans. n(X ∪ Y)= 44...Read full

Find how many students were taking either apple juice or orange juice.  In a survey of 400 students in a school, 100 were listed as taking apple juice, 150 as taking orange juice and 75 were listed as taking both apple as well as orange juice.

Ans. let A  be the student taking apple juice and B be the student taking orange juice ...Read full

If A = {2,3,4,5}, B = { 3,5,6,7} find the value ofA∪B and A∩B?

Ans. A∪B=2,3,4,5,6,7 ...Read full

Prove de morgan’s laws on union without using the venn diagram with example?

Ans. Let X=(A∪B)’...Read full