JEE Main 2022 · 27 Jun · Shift 1 · Mathematics Q6

MathematicsSingle correct+4 / -1Question 6 of 90

The number of distinct real roots of $x^4-4x+1=0$ is :

Answer and worked solution

Official answer: B

Turning point. $f'(x)=4x^3-4=0$ only at $x=1$ , where $f(1)=-2<0$ , while $f\to\infty$ on both sides.

Two real roots.

(B)

Topics:Monotonicity Theory of equations (higher degree)

JEE Main 2022 · 27 Jun · Shift 1, Mathematics question 6