10th Class Mathematics Polynomials Question Bank Assertion And Reason (MCQs) - Polynomials

  • question_answer
    Assertion   (A):   If   one   zero   of   polynomial\[p(x)=({{k}^{2}}+4){{x}^{2}}+13x+4k\]is reciprocal of other, then \[k=2\].
    Reason (R): If \[(x-\alpha )\] is a factor of \[p(x),\] then \[p(\alpha )=0\]i.e., \[\alpha \]is a zero of \[p(x)\].

    A) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

    B) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).

    C) Assertion (A) is true but reason (R) is false.

    D) Assertion (A) is false but reason (R) is true.

    Correct Answer: B

    Solution :

    [b] Let \[\alpha ,\frac{1}{\alpha }\]be the zeroes of \[p(x),\] then
    \[\alpha \cdot \frac{1}{\alpha }=\frac{4k}{{{k}^{2}}+4}\,\,\,\,\,\,\,\,\Rightarrow \,\,\,\,\,\,\,\,1=\frac{4k}{{{k}^{2}}+4}\]
    \[{{k}^{2}}-4k+4=0\,\,\,\,\,\,\,\Rightarrow \,\,\,{{(k-2)}^{2}}=0\]
    \[k=2\]
    Assertion is true. Since, reason is not correct for assertion.


You need to login to perform this action.
You will be redirected in 3 sec spinner