JAMIA MILLIA ISLAMIA Jamia Millia Islamia Solved Paper-2013

  • question_answer
        If\[\tan \theta =\alpha -\frac{1}{4\alpha },\]then\[\sec \theta -\tan \theta \]is equal to

    A)  \[-2a,\frac{1}{2a}\]                        

    B)  \[-\frac{1}{2a},2a\]

    C)  \[2a\]                                  

    D)  \[\frac{1}{2a},2a\]

    Correct Answer: A

    Solution :

                    Let       \[\sec \theta -\tan \theta =\lambda \]                  ...(i) Also,      \[\sec \theta +\tan \theta =\frac{1}{\lambda }\]                          ...(ii) On subtracting Eq. (i) from Eq. (ii), we get                 \[2\tan \theta =\frac{1}{\lambda }-\lambda \] \[\Rightarrow \]               \[2\left( a-\frac{1}{4a} \right)=\frac{1}{\lambda }-\lambda \] \[\Rightarrow \]               \[2a-\frac{1}{2a}=\frac{1}{\lambda }-\lambda \] \[\therefore \]  \[\lambda =\frac{1}{2a},-2a\]


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