FUNCTION 1. DEFINITION : If to every value (considered as real unless other-wise stated) of a variable \(\mathrm{x}\) , which belongs to a set \(\mathrm{A}\) , there corresponds one and only one finite value of the quantity \(y\) which belong to set \(B\) , then \(y\) is said to be a function of \(x\) and written as \(f: A \rightarrow B, y=f(x), x\) is called argument or independent variable and \(y\) is called dependent variable. Pictorially: \( \underset{\text { input }}{\stackrel{\mathrm{x}}{\longrightarrow}}\boxed{\mathrm{f}}\,\, \underset{\text { output }}{\stackrel{\mathrm{f(x)=y}}{\longrightarrow}}\) \(y\) is called the image of \(x\) and \(x\) is the pre-image of \(y\) , under mapping \(\mathrm{f}\) . Every function \(\mathrm{f}: \mathrm{A} \rightarrow \mathrm{B}\) satisfies the following conditions. (i) \(f \subset A \times B\) (ii) \(\forall \,\, a \in A \,\, \exists\,\, b \in B\) such that \((a, b) \in f\) and (iii) If \((a, b) \in f \) &...
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