4400 Higher November 2008 Paper 4 Q21

EdexcelHigherOld spec5 marksFunctions

21 The function f is defined as\[\mathrm{f}(x) = \frac{1}{x + 3}\]

(a) Find the value of \(\mathrm{f}(2)\) (1)
(b) State which value(s) of \(x\) must be excluded from the domain of f. (1)
(c) Given that \(\mathrm{f}(a) = \dfrac{1}{10}\), find the value of \(a\). (1)
(d) The function g is defined as\[\mathrm{g}(x) = x + 2\]Express the function gf in the form \(\mathrm{gf}(x) = .....\)
Give your answer as a single algebraic fraction in its simplest form. (2)