Question:
Construct a quadratic in x such that A.M. of its roots is A and G.M. is G.
Solution:
Let the roots of the quadratic equation be $a$ and $b$.
$A=\frac{a+b}{2}$
$\therefore a+b=2 A \quad \ldots \ldots \ldots(\mathrm{i})$
Also, $G^{2}=a b \quad \ldots \ldots$ (ii)
The quadratic equation having roots a and b is given by $x^{2}-(a+b) x+a b=0$.
$\therefore x^{2}-2 A x+G^{2}=0 \quad[$ Using (i) and (ii) $]$
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