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Example 16 - Chapter 1 Class 12 Relation and Functions
Last updated at Dec. 16, 2024 by Teachoo
Chapter 1 Class 12 Relation and Functions
Concept wise
- Relations - Definition
- Empty and Universal Relation
- To prove relation reflexive, transitive, symmetric and equivalent
- Finding number of relations
- Function - Definition
- To prove one-one & onto (injective, surjective, bijective)
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Composite functions
- Composite functions and one-one onto
- Finding Inverse
- Inverse of function: Proof questions
- Binary Operations - Definition
- Whether binary commutative/associative or not
- Binary operations: Identity element
- Binary operations: Inverse
Transcript
Example 16 Find gof and fog, if f : R → R and g : R → R are given by f (x) = cos x and g (x) = 3x2. Show that gof ≠ fog. f(x) = cos x , g(x) = 3x2 Hence, gof ≠ fog. f(x) = cos x f(g(x)) = cos g(x) fog(x) = cos (3x2) g(x) = 3x2 g(f(x)) = 3 f(x)2 gof (x) = 3 cos2 x
