JEE Main20206 Sep 2020Evening ShiftMathematicsQuadratic EquationActual
If α and β are the roots of the equation 2 x 2 x + 1 = 1 , then β is equal to :
Options
- A2 α α + 1
- B- 2 α α + 1
- C2 α α - 1
- D2 α 2
Correct answer
B. - 2 α α + 1
Step-by-step solution
Given equation is 2 x 2 x + 1 = 1 ⇒ 4 x 2 + 2 x - 1 = 0 .........(1) roots of equation 1 are α and β ∴ α + β = - 1 2 ⇒ β = - 1 2 - α ........(2) and 4 α 2 + 2 α - 1 = 0 ⇒ α 2 = 1 4 - α 2 .........(3) now - 2 α α + 1 = - 2 α 2 - 2 a = - 2 1 4 - α 2 - 2 α = - 1 2 - α = β