JEE Main & Advanced Sample Paper JEE Main Sample Paper-1

  • question_answer
    Direction: Question No. 92 is Assertion-Reason type question. These question contains two statements: Statement I (Assertion) and Statement II (Reason). These question also has four alternative choices, only one of which is the correct answer. You have to select the correct choice in the cedes (a), (b), (c) and (d) in the given below:  
    Statement I: If A is obtuse angle in \[\Delta ABC\], then tan B tan C > 1.
    Statement II: In \[\Delta ABC\] \[\tan A=\frac{\tan B+\tan C}{\tan B\tan C-1}\]
     

    A)  Statement I is true. Statement J fin true; Statement B is not a correct explanation for Statement I.

    B)  Statement I is true. Statement II is false.

    C)  Statement 1 is false. Statement S is true.

    D)  Statement I is true, Statement H is true; Statement H is a correct explanation for Statement I.

    Correct Answer: C

    Solution :

    Since, \[A+B+C=180{}^\circ \] \[\Rightarrow \]       \[A={{180}^{o}}-(B+C)\] \[\therefore \]\[\tan A=\tan [{{180}^{o}}-(B+C)]\] \[=-\tan (B+C)\] \[=-\left\{ \frac{\tan B+\tan C}{1-\tan B\tan C} \right\}\] \[=\frac{\tan B+\tan C}{\tan B\tan C-1}\]Since, A is obtuse. \[\therefore \]\[\tan A<0,\]then\[\tan B+\tan C>0\] \[\therefore \]\[\tan B\tan C-1<0\]\[\Rightarrow \]\[\tan B\tan C<1\] Hence, Statement I is false and Statement II is true.


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