Page 8 - ISC-12
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Single Correct Choice Type                            Jai Baba Ki5

                       1
          22. Let f :   , 1 → R (the set of all real numbers) be a positive, non-constant and differentiable function
                       2

                                              1
                         0
              such that f (x) < 2 f(x) and f      = 1. Then the value of
                                              2
                                                           1
                                                         Z
                                                             f(x) dx
                                                          1/2
              lies in the interval

                                                                      e − 1                      e − 1
               (A) (2e − 1, 2e).       (B) (e − 1, 2e − 1).     (C)         , e − 1 .   (D)   0,        .
                                                                        2                          2
                                                                                                    [JEE 2013]

                                                                                                         π
                                                                                                     h     i
          23. The area enclosed by the curves y = sin x + cos x and y = | cos x − sin x| over the interval 0,  is
                                                                                                         2
                     √                       √ √                      √                       √ √
               (A) 4( 2 − 1).          (B) 2 2( 2 − 1).         (C) 2( 2 + 1).          (D) 2 2( 2 + 1).
                                                                                                    [JEE 2013]
                                                 π                                                 y        y

          24. A curve passes through the point 1,   . Let the slope of the curve at each point (x, y) be +sec  ,
                                                 6                                                 x       x
              x > 0. Then the equation of the curve is
                        y             1                                     y

               (A) sin      = log x + .                         (B) cosec      = log x + 2.
                        x             2                                     x

                         2y                                               2y             1
               (C) sec        = log x + 2.                      (D) cos        = log x + .
                         x                                                x              2
                                                                                                    [JEE 2013]


                                23             n
                                P     −1       P
          25. The value of cot     cot    1 +     2k    is
                                n=1           k=1
                   23                       25                      23                       24
               (A)    .                (B)    .                 (C)    .                (D)     .
                   25                       23                      24                       23
                                                                                                    [JEE 2013]
                                                             x + 2    y + 1    z
          26. Perpendiculars are drawn from points on the line      =       =    to the plane x + y + z = 3. The
                                                               2       −1      3
              feet of perpendiculars lie on the line
                   x    y − 1    z − 2                               x    y − 1   z − 2
               (A)    =        =       .                        (B)    =        =       .
                   5      8       −13                                2      3       −5
                   x    y − 1    z − 2                               x    y − 1   z − 2
               (C)    =        =       .                        (D)    =        =       .
                   4      3       −7                                 2     −7        5

                                                                                                    [JEE 2013]
                  −→                      −→
                          ˆ
                              ˆ
                                    ˆ
                                                      ˆ
                                                           ˆ
                                                 ˆ
          27. Let PR = 3i + j − 2k and SQ = i − 3j − 4k determine diagonals of a parallelogram PQRS and
              −→
                              ˆ
                     ˆ
                         ˆ
              PT = i + 2j + 3k be another vector. Then the volume of the parallelepiped determined by the vectors
              −→ −→        −→
              PR, PQ and PS is
               (A) 5.                  (B) 20.                  (C) 10.                 (D) 30.
                                                                                                    [JEE 2013]
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