Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Applications of Derivatives

Question:

Rolle's theorem holds for the function $x^3+b x^2+c x, 1 \leq x \leq 2$ at the point $\frac{4}{3}$, the value of b and c are

Options:

b = 8, c = -5

b = -5, c = 8

b = 5, c = -8

b = -5, c = -8

Correct Answer:

b = -5, c = -8

Explanation:

f'(4/3) = 0

⇒ 16 + 8b + 3c = 0

Also f(1) = f(2)

⇒ 3b + c + 7 = 0

Hence b = –5, c = –8