JEE Main & Advanced Mathematics Binomial Theorem and Mathematical Induction Question Bank Self Evaluation Test - Binomial Theorem

  • question_answer
    The number of integral terms in the expansion of \[{{(\sqrt{3}+\sqrt[8]{5})}^{256}}\] is

    A) 35

    B) 32

    C) 33

    D) 34

    Correct Answer: C

    Solution :

    [c] \[{{T}_{r+1}}={{\,}^{256}}{{C}_{r}}{{(\sqrt{3})}^{256-r}}{{(\sqrt[8]{5})}^{r}}={{\,}^{256}}{{C}_{r}}{{(3)}^{\frac{256-r}{2}}}{{(5)}^{r/8}}\] Terms will be integral if \[\frac{256-r}{2}\And \frac{r}{8}\] both are +ve integer, which is so if r is an integral multiple of 8. As \[0\le r\le 256\] \[\therefore \,\,\,\,r=0,\,\,8,\,\,16,\,\,24,........256,\] total 33 values.


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