JEE PYQ: Application Of Derivatives Question 52
Question 52 - 2020 (08 Jan Shift 2)
Let $f(x)$ be a polynomial of degree 3 such that $f(-1) = 10$, $f(1) = -6$, $f(x)$ has a critical point at $x = -1$ and $f’(x)$ has a critical point at $x = 1$. Then $f(x)$ has a local minima at $x =$ ______.
Show Answer
Answer: 3
Solution
$f’(x) = a(x^2 - 2x - 3) = a(x-3)(x+1)$. From conditions: $a = \frac{3}{4}$, $c = -\frac{9}{4}$, $d = \frac{35}{4}$. $f(x)$ has local minimum at $x = 3$.
BETA
