Question

The middle term in the expansion of (1 – 3x + 3x² – x³)⁶ is ______.

Options

• ¹⁸C₁₀x¹⁰

• ¹⁸C₉(–x)⁹

• ¹⁸C₉x⁹

• ¹⁸C₉x¹⁰

Answer 1

The middle term in the expansion of (1 – 3x + 3x² – x³)⁶ is `underlinebb(""^18C_9(–x)^9)`.

Explanation:

(1 – 3x + 3x² – x³)⁶ = (1 – x)¹⁸

If n is even, then the middle term is `((n + 2)/n)`

Middle term is `(18 + 2)/2` = 10^th term

T₁₀ = ¹⁸C₉(–x)⁹