JEE Main & Advanced Mathematics Binomial Theorem and Mathematical Induction Question Bank General term, Coefficient of any power of x, Independent term, Middle term and Greatest term and Greatest coefficient

  • question_answer
    In the expansion of \[{{(1+x+{{x}^{3}}+{{x}^{4}})}^{10}},\] the coefficient of \[{{x}^{4}}\] is [MP PET 2000]

    A) \[^{40}{{C}_{4}}\]

    B) \[^{10}{{C}_{4}}\]

    C) 210

    D) 310

    Correct Answer: D

    Solution :

    \[{{(1+x+{{x}^{3}}+{{x}^{4}})}^{10}}={{(1+x)}^{10}}\,{{(1+{{x}^{3}})}^{10}}\] \[=(1+{}^{10}{{C}_{1}}\,.\,x+{}^{10}{{C}_{2}}\,.\,{{x}^{2}}+.....)\]\[(1+{}^{10}{{C}_{1}}\,.\,{{x}^{3}}+{}^{10}{{C}_{2}}\,.\,{{x}^{6}}+.....)\] \[\therefore \]Coefficient of \[{{x}^{4}}\] \[=\,{}^{10}{{C}_{1}}.{}^{10}{{C}_{1}}+{}^{10}{{C}_{4}}=310\].


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