Mathematics · Functions

JEE Main 2026 — 4 April, Morning Shift — Question 40

Let ff be a real polynomial of degree n such that f(x)=f′(x)f′′(x),f(x) = f'(x) f''(x), for all x∈R.Iff(0)=0,x ∈ ℝ. If f(0)=0, then 36[∫02f(x)dx+f′′(2)+f′(2)]36[∫_0^2 f(x)dx + f''(2) + f'(2)] is equal to :

  1. Option A:

    42

  2. Option B:

    46

  3. Option C:

    56

    Correct
  4. Option D:

    66

Answer: C

Step-by-step solution

Let degree of polynomial be ' n ' n=n−1+n−2⇒n=3\mathrm{n}=\mathrm{n}-1+\mathrm{n}-2 \Rightarrow \mathrm{n}=3 f(x)=ax3+bx2+cx\mathrm{f}(\mathrm{x})=\mathrm{ax}^{3}+\mathrm{bx}^{2}+\mathrm{cx} (ax3+bx2+cx)=(3ax2+2bx+c)(6ax+2b)\left(a x^{3}+b x^{2}+c x\right)=\left(3 a x^{2}+2 b x+c\right)(6 a x+2 b) x3:a=18a2⇒a=118x^{3}: a=18 a^{2} \Rightarrow a=\frac{1}{18} x2:b=6ab+12abx^{2}: b=6 a b+12 a b x:c=4b2+6ac⇒2C3=4b2⇒b2=c6x: c=4 b^{2}+6 a c \Rightarrow \frac{2 C}{3}=4 b^{2} \Rightarrow b^{2}=\frac{c}{6} const : bc=0⇒ b=c=0\mathrm{bc}=0 \Rightarrow \mathrm{~b}=\mathrm{c}=0

∫02f(x)dx+f′(2)+f′′(2)∫02ax3dx+12a+12a=4a+24a=28a=2818=14936(149)=56\begin{aligned} & \int_{0}^{2} f(x) d x+f^{\prime}(2)+f^{\prime \prime}(2) \\& \int_{0}^{2} a x^{3} d x+12 a+12 a=4 a+24 a=28 a=\frac{28}{18}=\frac{14}{9} \\& 36\left(\frac{14}{9}\right)=56 \end{aligned}

Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Subject
Mathematics
Chapter
Functions
Topic
Introduction to Functions