The coefficient of x 4 in the expansion of 1 + x + x 2 + x 3 6 in powers of x , is … . .

Question

The coefficient of x 4 in the expansion of 1 + x + x 2 + x 3 6 in powers of x , is &#8230; . .

Aicharya · Accepted Answer

1 + x + x 2 + x 3 6 = 1 + x 6 1 + x 2 6 Coefficient of x 4 = C 4 6 + C 2 6 &#183; C 1 6 + C 2 6 = 15 + 15 &#183; 6 + 15 = 120 .

The coefficient of x 4 in the expansion of 1 + x + x 2 + x 3 6 in powers of x , is &#8230; . .