Mathbee CBSE Mathbee · CBSE Class 12 Maths
Class 12 Continuity And Differentiability · Long Answer3 Markschain_and_product_rules

Class 12 Maths · Continuity And Differentiability · Long Answer #134

Let f(x)=√(x²+1), g(x)=(x+1)/(x²+1), h(x)=2x−3. Evaluate f′(h′(g′(x))).

✅ Step-by-Step Solution

Final Answer: 2/√5
  1. First f′(u)=u/√(u²+1), by the chain rule.
  2. The quotient rule gives g′(x)=[(x²+1)−2x(x+1)]/(x²+1)²=(1−2x−x²)/(x²+1)².
  3. For every input v, h′(v)=2. Hence h′(g′(x))=2 and f′(h′(g′(x)))=f′(2).
  4. Therefore the requested value is 2/√5.

📋 CBSE Stepwise Marking Scheme

  • [0.5 marks] First f′(u)=u/√(u²+1), by the chain rule.
  • [1 mark] The quotient rule gives g′(x)=[(x²+1)−2x(x+1)]/(x²+1)²=(1−2x−x²)/(x²+1)².
  • [1 mark] For every input v, h′(v)=2. Hence h′(g′(x))=2 and f′(h′(g′(x)))=f′(2).
  • [0.5 marks] Therefore the requested value is 2/√5.

Master Chapter 5: Continuity And Differentiability

Practise interactive questions, flashcards, visual mind maps, and timed board tests for Continuity And Differentiability.
📘 Chapter Notes & All Exercises 🚀 Open in Interactive Workspace →
← Previous Question
Differentiate y=\(x^{x \cos{\left(x \right)}} + \log{\left(x…
Next Question →
Differentiate y=\(x^{3} \cos^{x}{\left(x \right)} +…

More Practice Questions in Continuity And Differentiability

Related Questions in Continuity And Differentiability