Question

The coefficient of x99 in the expansion of (x - 1).
(x - 2)(x – 3) ..... (x - 100) is​

Answer 1

Answer:

5050

Step-by-step explanation:

= x^100 - x^99(1+2+...+100) + x^98(1×2 + 2×3+.....99×100) +......

hence coeff of x^99 = 1+2+3+....+100

= 100 ×101/2

=5050

Note : 1+2+.....= n(n+1)/2