10th Class Mathematics Polynomials Question Bank Case Based (MCQs) - Polynomials

  • question_answer
    The value of \[{{\alpha }^{3}}-{{\beta }^{3}}\]is:

    A) \[\frac{-539}{192\sqrt{3}}\]

    B) \[\frac{539}{192\sqrt{3}}\]

    C) \[\frac{539\sqrt{3}}{192}\]

    D) \[\frac{-539\sqrt{3}}{192}\]

    Correct Answer: B

    Solution :

    \[{{\alpha }^{3}}-{{\beta }^{3}}=(\alpha -\beta )\,\,({{\alpha }^{2}}+\alpha \beta +{{\beta }^{2}})\]
    \[=\left( \frac{-2}{\sqrt{3}}-\frac{\sqrt{3}}{4} \right)\,\,\left( \frac{4}{3}-\frac{1}{2}+\frac{3}{16} \right)\]
    \[=\left( \frac{-8-3}{4\sqrt{3}} \right)\times \frac{49}{48}\]
    \[=\frac{-539}{192\sqrt{3}}\]
    So, option [b] is correct.


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