Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
KVPY2020MathematicsBasics of Mathematics

Let x ,   y be real numbers such that x > 2 y > 0 and 2 log x - 2 y = log x + log y . Then the possible value s of x y

Options

  1. Ais 1 only
  2. Bare 1 and 4
  3. Cis 4 only
  4. Dis 8 only

Correct answer

C. is 4 only

Step-by-step solution

log x − 2 y 2 = log x y ⇒ x − 2 y 2 = x y ⇒ x − 2 y y 2 = x y ⇒ x y 2 − 5 x y + 4 = 0 ⇒ x y = 1 , 4 ⇒ x y = 4   as   x y > 2

Practice Basics of Mathematics on Quantrex Academy →

More from Basics of Mathematics

All Basics of Mathematics questions Full Basics of Mathematics list All KVPY PYQs