CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2008

  • question_answer
    In a triangle ABC,\[\frac{\cos A}{a}=\frac{\cos B}{b}=\frac{\cos C}{c}.\]If\[a=\frac{1}{\sqrt{6}},\]then the area of the triangle (in square units) is

    A)  1/24                     

    B)         \[\sqrt{3}/24\]

    C)  1/8                       

    D)         \[1/\sqrt{3}\]

    E)  \[5/12\sqrt{3}\]

    Correct Answer: B

    Solution :

    Since, \[\frac{\cos A}{a}=\frac{\cos B}{b}=\frac{\cos C}{c}\] \[\Rightarrow \]               \[\frac{\cos A}{k\sin A}=\frac{\cos B}{k\sin B}=\frac{\cos C}{k\sin C}\] \[\Rightarrow \]               \[\cot A=\cot B=\cot C\] \[\Rightarrow \]               \[A=B=C=60{}^\circ \] \[\Rightarrow \] \[\Delta ABC\]is an equilateral triangle. \[\therefore \] \[\Delta =\frac{\sqrt{3}}{4}{{a}^{2}}=\frac{\sqrt{3}}{4}\times \frac{1}{6}\]                                 \[=\frac{\sqrt{3}}{24}sq\,unit\]


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