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(a + b)ⁿ

ADV003 · Advanced mathematics · Classes 11–12 + B.Tech

Binomial theorem

The binomial theorem expands (a + b)ⁿ into n + 1 terms with coefficients C(n, k). The general term is C(n, k) aⁿ⁻ᵏ bᵏ.

📐 Formula

(a + b)ⁿ = Σₖ C(n, k) aⁿ⁻ᵏ bᵏ; Tₖ₊₁ = C(n, k) aⁿ⁻ᵏ bᵏ

✏️ Worked example

(x + 1)⁵ = x⁵ + 5x⁴ + 10x³ + 10x² + 5x + 1.

🌍 Where it is used

Probability of k successes, approximations like 1.02¹⁰.

❓ Quick check

Coefficient of x² in (1 + x)⁴?

🏋️ Practice

EasyNumber of terms in (a + b)⁷?

Answer: 8

MediumMiddle term of (x + 1)⁶?

Answer: 20x³

ChallengeApproximate 1.01⁵ using two terms.

Answer: 1 + 5 × 0.01 = 1.05