KVPY2018MathematicsQuadratic Equation
The number of real roots of the polynomial equation x 4 - x 2 + 2 x - 1 = 0 is
Options
- A0
- B2
- C3
- D4
Correct answer
B. 2
Step-by-step solution
Given, 4 - x 2 + 2 x - 1 = 0 ⇒    x 4 - ( x - 1 ) 2 = 0 ⇒ x 2 - x + 1 x 2 + x - 1 = 0 ⇒ x 2 - x + 1 = 0 or x 2 + x - 1 = 0 ⇒ x 2 - x + 1 = 0 has no real roots. ⇒ x 2 + x - 1 = 0 has two real roots