Q35 / 54 · JEE Advanced 2020 (Paper 1) · Mathematics
For a polynomial with real coefficients, let denote the number of distinct real roots of . Suppose is the set of polynomials with real coefficients defined by . For a polynomial , let and denote its first and second order derivatives respectively. Then the minimum possible value of , where , is ____
Correct answer: 5
Solution
is a polynomial in such that
So, where is polynomial roots of
So, by Rolle’s theorem, , where
minimum
Again by Rolle’s theorem, at least one real root lies in and at least one real root lies in of
So, minimum
Minimum possible value of
Hence, the correct answer is 5.