Example 18 Show that if f : A → B and g : B → C are one-one, then gof : A → C is also one-one. Checking gof one-one We need to prove that If gof (x1) = gof (x2), then x1 = x2 Suppose gof (x1) = gof (x2) g (f (x1)) = g(f (x2)) Given g is one-one So, f (x1) = f (x2), And f is also one-one x1 = x2 Hence, gof is one-one.

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Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.

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