Question:
Find the value of $k$ for which the roots of the equation $3 x^{2}-10 x+k=0$ are reciprocal of each other.
Solution:
Let one root be $\alpha$ and the other root be $\frac{1}{\alpha}$.
The given equation is $3 x^{2}-10 x+k=0$.
Product of roots $=\frac{k}{3}$
$\Rightarrow \alpha \times \frac{1}{\alpha}=\frac{k}{3}$
$\Rightarrow 1=\frac{k}{3}$
$\Rightarrow k=3$
Hence, the value of $k$ for which the roots of the equation $3 x^{2}-10 x+k=0$ are reciprocal of each other is 3 .