[Maths Class Notes] on Conjunction in Maths Pdf for Exam

Logical reasoning finds its applications in several problem-solving strategies in Mathematics. It is easy to deduce the conclusions of certain problems on the basis of the facts and through the application of the Mathematical principles. In Mathematics for solving problems, different Logical Connectors are used to connect two simple Mathematical and Logical statements to form compound statements. The two types of connectors used are known as Conjunction and Disjunction. Conjunctions (“and”) are represented by the Mathematical symbol “^ “and Disjunctions (“or”) are represented by the Mathematical symbol “˅.” 

Further, we will discuss different aspects of Conjunctions and their applications. 

Conjunction in Math

In Mathematics, a Conjunction refers to a Connector added between two statements. The connection is done through the keyword “AND”. The Mathematical symbol or the Conjunction symbol which represents Conjunction is “^”, and this symbol can be read as “AND”. 

If we denote two statements as p and q then according to the Conjunction meaning, they can be connected by the symbol “^”.

So, it becomes, p ^ q.  This compound statement can be read as “p and q”. This statement will be true only if both the statements p and q are true; otherwise, this statement will be false. We will further see all the combinations and Conjunction rules by understanding the Conjunction Truth Table.

Logic Statements

With the help of Logic statements, we can label a statement as true or false. For example, 

• All numbers fall under integers

• All squares are rectangles

• All rectangles possess four sides

• Some negative numbers fall under integers

• Some quadrilaterals are termed parallelograms. 

It is quite clear that some of these statements given above are false. But these are all tesTable claims and do not express any particular opinion. 

Logic Connectors

The statements are often shown with the letters p and q and are connected together with the use of Connectors. That is, one can combine ideas with the use of the words ‘and’ or ‘or’. The two different statements that are connected with the use of these Connectors form the compound statements. These two Connectors are called Conjunctions in Mathematics. The Conjunctions make use of the Mathematical symbols “^”, while Disjunctions use the symbol “v”. 

Conjunction Examples

Let us define a Conjunction with an example. For instance, 

If our statement 1 is: Karan likes chocolate ice-cream, and our statement 2 is: Riya likes blueberry ice cream, then to connect them we use the Connector of Conjunction through the keyword “and”. After connecting, our statement becomes, “Karan likes chocolate ice-cream, and Riya likes blueberry ice-cream”. For this statement to be true, both statement 1 and statement 2 need to be true; otherwise, the new statement becomes false. 

Rules of Conjunction

• The statement after adding the Conjunction Connector “and” will be true only if the individual statements are true in the first place; otherwise, the new statement formed will be false. 

• The rules are in line with the rules of the AND Logic gate.

• The symbol for Conjunction is “^” which represents the word “AND” which is a type of a Logical Connector. 

• When considering statements, we denote them using alphabetical letters when representing them. In that terms, we can define Conjunction as, let two statements be p and q. The statement after adding a Conjunction Connector becomes a compound statement and is represented as “p ^ q”, and it is read as “p and q”.

What is a Conjunction Truth Table? 

The Truth Table is especially important to understand the final values of the compound statements depending on the values of individual statements. All possible combinations are covered in this Conjunction Truth Table. Here “T”  letter is used to indicate True value and “F” letter is used to indicate false value.

The Truth Table for Conjunction (“AND”)

From the Truth Table we can clearly deduce the value of the compound statement “p ^ q” will ONLY be true if both, statement p and statement q have true values individually. In all other cases the value of “p ^ q” will be false. 

Disjunctions

When there is the use of the Connector ‘or’ between two statements , then we have  a Disjunction. In this situation, one one statement in this compound statement is true in order to make the whole compound statement true. 

Given below are some true statements

• All numbers fall under integers

• All squares are rectangles

• All rectangles have four sides. 

• All quadrilaterals have 11 sides. 

• Some quadrilaterals can be called parallelogram

If we join together one true and one false statement using the Connector ‘or’, we will obtain a true compound statement. 

That is , if p = all squares are rectangles, and 

          
      q= all quadrilaterals have 11 sides

Then p v q=  all squares are rectangles or all quadiaterlas have 11 sides. 

Examples of Disjunction and Conjunction

1. P = some negative numbers are integers

Q = all squares are rectangles

P^Q =  some negative numbers are integers and all squares are rectangles. 

We use the Connector ‘and’ as both the sentences are true.

2. P = some quadrilaterals are called parallelograms

Q = all quadrilaterals have 11 sides.

P v Q = some quadrilaterals are called parallelograms or all quadrilaterals have 11 sides.

We use the Connector ‘or’ because the statement all quadrilaterals have 11 sides is false, but the use of the Conjunction ‘or’ makes the compound statement true since the statement all quadrilaterals are parallelograms is true. 

Solved Problems

Here are some solved problems for a better understanding of the Conjunction meaning and examples.

1. Let 4 be a rational number and let 7 be a prime number. Is this a Conjunction? 

Ans: Let statement p be that 4 is a rational number 

Statement p is TRUE. 

Let statement q be that 7 is a prime number 

Statement q is TRUE

As per the Truth Table, if p is True and if q is also true, then “p ^ q” is True

So, in our case, the Conjunction “p ^ q” that is “4 is a rational number, and 7 is a prime number” is True. 

2. A: The sun rises in the east 

B: It will definitely rain day after tomorrow 

Is this a true Conjunction? 

Ans: Statement A which states that the sun rises in the east is a True fact and hence can never be changed. So, statement A is True. 

Statement B has the possibility to be false or True. A prediction can never be made with 100% surety that it will definitely rain the day after tomorrow. Thus, statement B has both possibilities. But, for sure, it cannot be proved as a totally True statement at present. Hence, statement B is False. 

So, according to the Truth Table, the Conjunction A^B is False. 

3. Given :

A = a square is quadrilateral

B = Harrison Ford is an American actor.

The Truth Table for the given problem is 

4. Given 

R = the number x is odd

S = the number x is prime