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Please Solve R.D. Sharma class 12 Chapter relations Exercise 1.1 Question 12  Maths textbook Solution.

Answers (1)

Answer:

The relation having properties of being transitive and reflexive but not symmetric.

Hint:

A relation R on set A is

 Reflexive relation:

If (a, a) \in R for every a \in A

Symmetric relation:

If \left ( a,b \right ) is true then \left ( b,a \right )is also true for every a, b \in A

Transitive relation:

If (a, b) \text { and }(b, c) \in R, then (a, c) \in R  for every a, b, c \in A

Given:

 An integer m  is said to be related to another integer n if m is multiple of n

Solution:

Reflexivity:

\begin{aligned} &\text { Let } m \in Z \\ &m=1 . m \\ &(m, m) \in R \end{aligned}

R is reflexive.

Symmetric:

\begin{aligned} &\text {Let }(a, b) \in R \\ &\Rightarrow \quad a=k b \\ &\Rightarrow \quad b=\frac{1}{k} a \quad \text { but } \frac{1}{k} \notin z \text { if } k \in z \\ &\therefore \quad(b, a) \notin R \end{aligned}

R  is not symmetric.

Transitive:

\begin{aligned} &\text { Let }(a, b) \in R \text { and }(b, c) \in R \\ &a=k b \text { and } b=k^{\prime} c \end{aligned}

Then,  \begin{aligned} a=k k^{\prime} c &\left[k k^{\prime} \in Z\right] \\ a=I c &\left[I=k k^{\prime} \in Z\right] \\ (a, c) \in R & \end{aligned}

 R is transitive.

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