If one of the roots of `x^2+(1+k)x+2k=0` is twice the other, then `(a^2+b^2)/(ab)=`

Options

A. 2
B. 1
C. 4
D. 7

Answer

D

Explanation

(i) Use of the concept of sum and product of the roots of a quadratic equation.
(ii) Assume the roots as `alpha` and `2alpha`.
(iii) Find the sum of the roots and product of the roots.
(iv) From the above equation eliminate `'alpha'` .
(v) Then obtain the value of `(k^(2) + 1)/(k)`.