COMEDK2024MathematicsBinomial Theorem
The total number of terms in (x-y)²⁰+(x+y)²⁰ is
Options
- A10
- B20
- C21
- D11
Correct answer
D. 11
Step-by-step solution
By using binomial expansion (x+y)²⁰= ²⁰ C₀ x²⁰+ ²⁰ C₁ x¹⁹ y+ ²⁰ C₂ x¹⁸ y^2+ 20 20 y²⁰ ...(i) and (x-y)²⁰= ²⁰ C₀ x²⁰- ²⁰ C₁ x¹⁹ y+ ²⁰ C₂ x¹⁸ y^2 - + 20 20 y²⁰ ...(ii) Add both the Eqs. (i) and (ii), array r (x+y)²⁰+(x-y)²⁰=2 [ ²⁰ C₀ x²⁰+ ²⁰ C₂ x¹⁸ y^2 + + 20 20 y²⁰ ] array Total number of terms =11