Question
Two functions f and g are defined on a suitable domain by f(x)=x^(2)-1 and g(x)=x^(2)+2 . a) Find a formula for f(g(x)) . b) Factorise f(g(x)) .
Answer
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(199 Votes)
Seth
Elite · Tutor for 8 years
Answer
a) \(f(g(x)) = x^4 + 4x^2 + 3\)b) \(f(g(x)) = (x^2 + 1)(x^2 + 3)\)
Explanation
1. To find a formula for \(f(g(x))\), we need to substitute \(g(x)\) into \(f(x)\). Given \(f(x) = x^2 - 1\) and \(g(x) = x^2 + 2\), we get:
Expanding the expression, we obtain:
2. To factorise \(f(g(x))\), we factorise the polynomial
. The factorisation is: