KVPY Sample Paper KVPY Stream-SX Model Paper-26

  • question_answer
    If the product of the intercepts made by the line \[x\tan \alpha +y\sec \alpha =1\] on the coordinate axes is sin \[\alpha \] then a is equal to

    A) \[\frac{\pi }{4}\]

    B) \[\frac{\pi }{2}\]        

    C) \[\pi \]   

    D) \[0\]

    Correct Answer: A

    Solution :

    We have, \[x\,\tan \alpha +y\sec \alpha =1\]
    \[\frac{x}{\cot \alpha }+\frac{y}{\cos \alpha }=1\]
    Intercept are cot\[\alpha \] and cos \[\alpha \]. Given,  \[\cot \alpha .\cos \alpha =\sin \alpha \]
    \[{{\tan }^{2}}\alpha =1\] \[\Rightarrow \,\,\,\,\,\tan \alpha =\pm 1\]
    \[\alpha =\pm \frac{\pi }{4}\Rightarrow \alpha =\frac{\pi }{4}\]


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