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Home  >>  CBSE XI  >>  Math  >>  Binomial Theorem

The total number of terms in the expansion of $(x+a)^{100}+(x-a)^{100}$ after simplification is

$\begin{array}{1 1}(A)\;50\\(B)\;202\\(C)\;51\\(D)\;\text{None of these}\end{array} $

1 Answer

Toolbox:
  • $(a+b)^n=nC_0a^n+nC_1a^{n-1}b^1+nC_2a^{n-2}b^2+.....nC_ra^{n-r} b^r+nC_n b^n$
$(x+a)^{100}+(x-a)^{100}$
$2[100C_0 x^{100}a^0+100C_2 x^{98}a^2+.....+100C_{100}x^0a^{100}]$
$\Rightarrow 2x^{100}+2^{100}C_2x^{98}a^2+....2a^{100}$
Hence there are 51 terms.
Hence (C) is the correct answer.
answered Jun 24, 2014 by sreemathi.v
 
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