JAMIA MILLIA ISLAMIA Jamia Millia Islamia Solved Paper-2011

  • question_answer
        If the ratio of the roots of\[a{{x}^{2}}+2bx+c=0\]is same as the ratio of the\[p{{x}^{2}}+2qx+r=0,\]then

    A)  \[\frac{2b}{ac}=\frac{{{q}^{2}}}{pr}\]                    

    B)  \[\frac{b}{ac}=\frac{q}{pr}\]

    C)  \[\frac{{{b}^{2}}}{ac}=\frac{{{q}^{2}}}{pr}\]                       

    D)  None of these

    Correct Answer: C

    Solution :

                    Let\[\alpha ,\beta \]be the roots of the equation \[a{{x}^{2}}+2bx+c=0\]and\[y,\delta \]be the roots of the equation\[p{{x}^{2}}+2qx+r=0\]be Also, given \[\frac{\alpha }{\beta }=\frac{\gamma }{\delta }\Rightarrow \frac{\alpha }{\gamma }=\frac{\beta }{\delta }\] \[\Rightarrow \]               \[\frac{\alpha +\beta }{\gamma +\delta }=\sqrt{\frac{\alpha \beta }{\gamma \delta }}\] \[\Rightarrow \]               \[\frac{-2b/a}{-2q/p}=\sqrt{\frac{c/a}{r/p}}\] \[\Rightarrow \]               \[\frac{{{b}^{2}}}{ac}=\frac{{{q}^{2}}}{pr}\]


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