JEE Main & Advanced Sample Paper JEE Main Sample Paper-11

  • question_answer
    Consider the family of straight lines \[2x{{\sin }^{2}}\theta +y{{\cos }^{2}}\theta =2\cos 2\theta \]
    Statement 1: All the lines of the given family pass through the point (3, -2).
    Statement 2: All the lines of the given family pass through a fixed point.

    A)  Statement-1 is false, Statement-2 is true.

    B)  Statement-1 is true, Statement-2 is true and Statement-2 is correct explanation for statement-1

    C)  Statement-1 is true, Statement-2 is true and Statement-2 is NOT correct explanation for statement-1

    D)  Statement-11s true, Statement-2 is false.

    Correct Answer: A

    Solution :

     \[2{{\sin }^{2}}\theta x+{{\cos }^{2}}\theta y=2\cos 2\theta \] Statement-1: The line passes through the point (3,-2) If \[6{{\sin }^{2}}\theta -2{{\cos }^{2}}\theta =2\cos 2\theta \] i.e. \[6(1-{{\cos }^{2}}\theta )-2{{\cos }^{2}}\theta =4{{\cos }^{2}}\theta -2\] Family of lines passes through the point of intersection of line 2 x - y + 4 = 0 and x = - 1 \[\therefore \]The point is (-1,2) \[\therefore \]Statement-2 is true.


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