Binomial Theorem And Its Simple Applications Question 139

Question: In the polynomial $ (x-1)(x-2)(x-3)………….(x-100), $ the coefficient of $ x^{99} $ is

[AMU 2002]

Options:

A) 5050

B) - 5050

C) 100

D) 99

Show Answer

Answer:

Correct Answer: B

Solution:

  • $ (x-1)(x-2)(x-3)….(x-100) $

Number of terms = 100;

Coefficient of x99 = $ (x-1)(x-2)(x-3)…(x-100) $ = $ (-1-2-3-……-100) $ =

$ -(1+2+…..+100) $ = $ -\frac{100\times 101}{2} $ = - 5050.