Let A be a real number. Then the roots of the equation x2 - 4x - log2A = 0 are real and distinct if and only if
Explanation:
For roots of a quadratic equation to be real and distinct, Discriminant > 0
So, for x2 − 4x – log2A = 0,
D = (-4)2 - (4 × 1 × (-log2A)) > 0
⇒ 16 + 4 × log2A > 0
⇒ log2A > -4
⇒ A > 2-4
⇒ A > 1/16
Hence, option (d).
» Your doubt will be displayed only after approval.
Help us build a Free and Comprehensive Preparation portal for various competitive exams by providing us your valuable feedback about Apti4All and how it can be improved.