Binomial Theorem And Its Simple Applications Question 149

Question: The coefficient of $ x^{100} $ in the expansion of $ \sum\limits_{j=0}^{200}{{{(1+x)}^{j}}} $ is

[UPSEAT 2004]

Options:

A) $ ( \begin{aligned} & 200 \\ & 100 \\ \end{aligned} ) $

B) $ ( \begin{aligned} & 201 \\ & 102 \\ \end{aligned} ) $

C) $ ( \begin{aligned} & 200 \\ & 101 \\ \end{aligned} ) $

D) $ ( \begin{aligned} & 201 \\ & 100 \\ \end{aligned} ) $

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Answer:

Correct Answer: A

Solution:

  • $ {T_{r+1}}={{,}^{200}}C_{r}{{(1)}^{200-r}}.{{(x)}^{r}} $

Hence coefficient of $ x^{100}={{,}^{200}}C_{100}=( \begin{aligned} & 200 \\ & 100 \\ \end{aligned} ) $ .