Question

If $(a,\frac{1}{a}),(b,\frac{1}{b}),(c,\frac{1}{c})\&(d,\frac{1}{d})$ are four distinct points on a circle of radius 4 units then, abcd is equal to

• A. 4
• B.
• C. 1
• D. 16

Answer 1

The correct option is C 1

Solving $x^2+y^2+2gx+2fy+k=0$ and xy = 1
$x^2+\frac{1}{x^2}+2gx+\frac{2f}{x}+k=0$
$\Rightarrow x^4+2g{x}^3+k{x}^3+2gx+1=0$
Product of the roots $S_4=1\Rightarrow abcd=1$