Definition: Composition (of functions)

Definition: Let f:A\rightarrow B and g:B\rightarrow C be two functions, with their domains and codomains as written.  The composition of f and g, denoted by g\circ f, is the function g\circ f: A\rightarrow C that takes a\in A to g(f(a))\in C—this last phrase is often denoted by a\mapsto g(f(a)).  In other words, g\circ f(a)=g(f(a)).

This is an extremely important definition, and for more details check out lesson 31!


2 Responses to Definition: Composition (of functions)

  1. thami says:

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    • My pleasure! I’m glad to hear that you like site 🙂 And if you like the site then I’m sure you’ll also like the book that just got published, see the most recent blog post for a link to it (it’s also on Amazon now too). I hope you continue to enjoy! 🙂 🙂

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