MHT CET · Maths · Differentiation
If \(\mathrm{f}(1)=1, \mathrm{f}^{\prime}(1)=3\), then the derivative of \(\mathrm{f}(\mathrm{f}(\mathrm{f}(x)))+(\mathrm{f}(x))^2\) at \(x=1\) is
- A 12
- B 30
- C 15
- D 33
Answer & Solution
Correct Answer
(D) 33
Step-by-step Solution
Detailed explanation
\(\begin{aligned} \text { Let } y & =\mathrm{f}(\mathrm{f}(\mathrm{f}(x)))+(\mathrm{f}(x))^2 \\ \therefore \quad & \frac{\mathrm{~d} y}{\mathrm{~d} x}=\mathrm{f}^{\prime}(\mathrm{f}(\mathrm{f}(x))) \cdot \mathrm{f}^{\prime}(\mathrm{f}(x)) \cdot \mathrm{f}^{\prime}(x)+2 \mathrm{f}(x) \mathrm{f}^{\prime}(x)\end{aligned}\)
\(\begin{aligned}\left.\frac{\mathrm{d} y}{\mathrm{~d} x}\right|_{x=1} & =\mathrm{f}^{\prime}(\mathrm{f}(\mathrm{f}(1))) \cdot \mathrm{f}^{\prime}(\mathrm{f}(1)) \cdot \mathrm{f}^{\prime}(1)+2 \mathrm{f}(1) \mathrm{f}^{\prime}(1) \\ & =3 \cdot 3 \cdot 3+2 \cdot 1 \cdot 3 \\ & =33\end{aligned}\)
\(\begin{aligned}\left.\frac{\mathrm{d} y}{\mathrm{~d} x}\right|_{x=1} & =\mathrm{f}^{\prime}(\mathrm{f}(\mathrm{f}(1))) \cdot \mathrm{f}^{\prime}(\mathrm{f}(1)) \cdot \mathrm{f}^{\prime}(1)+2 \mathrm{f}(1) \mathrm{f}^{\prime}(1) \\ & =3 \cdot 3 \cdot 3+2 \cdot 1 \cdot 3 \\ & =33\end{aligned}\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Maths
- For the probability distribution given by following

\(\operatorname{Var}(\mathrm{X})=\)MHT CET 2021 Medium - For the inequalities \(x+y \leq 3,2 x+5 y \geq 10, x \geq 0, y \geq 0\), which of the following points lies in the feasible region?MHT CET 2022 Easy
- The particular solution of the differential equation, \(x y \frac{\mathrm{~d} y}{\mathrm{~d} x}=x^2+2 y^2\) when \(y(1)=0\) isMHT CET 2024 Hard
- The equation of a curve passing through \((1,0)\) and having slope of tangent at any point \((\mathrm{x}, \mathrm{y})\) of the curve as \(\frac{\mathrm{y}-1}{x^2+x}\) isMHT CET 2025 Medium
- If \(X \sim B\left(8, \frac{1}{2}\right)\), then \(P(|x-4| \leq 2)=\)MHT CET 2020 Medium
- If \(|\bar{a} \times \bar{b}|^2+(\bar{a} \cdot \bar{b})^2=144\) and \(|\bar{a}|=4\), then \(|\bar{b}|=\)MHT CET 2021 Easy
More PYQs from MHT CET
- Which among the following is NOT allylic halide?MHT CET 2024 Easy
- What type of following phenomena does the Cannizzaro reaction exhibit?MHT CET 2023 Easy
- Which one of the following is NOT a symptom of Typhoid?MHT CET 2025 Easy
- The contrapositive of the inverse of \(\mathrm{p} \rightarrow(\mathrm{p} \rightarrow \mathrm{q})\) isMHT CET 2024 Easy
- Anticodon loop of tRNA has ________.MHT CET 2025 Easy
- \(\int_{2}^{3} \frac{d x}{x^{2}+x}=\)MHT CET 2020 Easy