हिंदी

Let L be the set of all lines in XY plane and R be the relation in L defined as R = {(L1, L2): L1 is parallel to L2}. Show that R is an equivalence relation. Find the set of all lines related to the - Mathematics

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प्रश्न

Let L be the set of all lines in XY plane and R be the relation in L defined as R = {(L1, L2): L1 is parallel to L2}. Show that R is an equivalence relation. Find the set of all lines related to the line y = 2x + 4.

योग

उत्तर

(i) Reflexive 

R = {(L1, L2): L1 is parallel to L2}

R is reflexive as any line L1 is parallel to itself, i.e., (L1, L1) ∈ R.

∴ R is reflexive

(ii) Symmetric

Now, let (L1, L2) ∈ R

⇒ L1 is parallel to L2

⇒ L2 is parallel to L1

⇒ (L2, L1) ∈ R

∴ R is symmetric

(iii) Transitive

Now, let (L1, L2), (L2, L3) ∈ R

⇒ L1 is parallel to L2. Also, L2 is parallel to L3

⇒ L1 is parallel to L3

∴R is transitive

Hence, R is an equivalence relation

The set of all lines related to the line y = 2x + 4 is the set of all lines that are parallel to the line y = 2x+ 4

Slope of line y = 2x + 4 is m = 2

It is known that parallel lines have the same slopes

The line parallel to the given line is of the form y = 2x + c, where c ∈ R

Hence, the set of all lines related to the given line is given by y = 2x + c, where c ∈ R

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अध्याय 1: Relations and Functions - Exercise 1.1 [पृष्ठ ६]

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एनसीईआरटी Mathematics [English] Class 12
अध्याय 1 Relations and Functions
Exercise 1.1 | Q 14 | पृष्ठ ६

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