Question

The coefficient of $(1 + x + x^{2} + ....)^{2}$` $n + 1$ is.

• A. – 56
• B. 56
• C. – 14
• D. 14

Answer 1

Answer: (C)

– 14

Answer 2

$\Rightarrow 2^{300} \times 2 \equiv (1.2)$

Thus coefficient of x⁷ is

$\Rightarrow 2^{301} \equiv 2$.