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📋 Key Definitions and Core Concepts
Product Rule: d/dx[uv] = u(dv/dx) + v(du/dx).
Integration by Parts: ∫ u (dv/dx) dx = uv - ∫ v (du/dx) dx.
🔍 Key Principles & Specification Requirements
- Standard derivatives: d/dx[e^{kx}] = k e^{kx}, d/dx[ln x] = 1/x, d/dx[tan kx] = k sec² kx.
- Parametric: dy/dx = (dy/dt) / (dx/dt); d²y/dx² = [d/dt(dy/dx)] / (dx/dt).
- Separable differential equations: ∫ (1/g(y)) dy = ∫ f(x) dx + C.
💡 Worked Example Question
Exam-Style Question
Question:
Evaluate ∫₀¹ x e²ˣ dx using integration by parts.
Model Solution & Mark Scheme:
u = x => du = dx; dv = e²ˣ dx => v = ½e²ˣ.
[½x e²ˣ]₀¹ - ∫₀¹ ½e²ˣ dx = ½e² - [¼e²ˣ]₀¹ = ¼e² + ¼.
❓ Practice Questions & Mark Schemes
Q1: Differentiate y = (x² + 1) e³ˣ.
Show Model Answer
Answer: dy/dx = 2x e³ˣ + 3(x² + 1) e³ˣ = e³ˣ(3x² + 2x + 3).
Q2: Solve dy/dx = 2xy with y(0) = 3.
Show Model Answer
Answer: ∫ (1/y) dy = ∫ 2x dx => ln y = x² + C => y = 3e^{x²}.
📄 Past Papers & Exam Resources
🔗 Further Reading & Resources