JEE MAIN - Mathematics (2018 (Offline))

  • 1
    From 6 different novels and 3 different dictionaries, 4 novels and 1 dictionary are to be selected and arranged in a row on a shelf so that the dictionary is always in the middle. The number of such arrangements is :
    პასუხი
    (B)
    at least 1000
  • 2
    Let S = { $$x$$ $$ \in $$ R : $$x$$ $$ \ge $$ 0 and

    $$2\left| {\sqrt x - 3} \right| + \sqrt x \left( {\sqrt x - 6} \right) + 6 = 0$$}. Then S
    პასუხი
    (D)
    contains exactly two elements
  • 3
    If $$\alpha ,\beta \in C$$ are the distinct roots of the equation
    x2 - x + 1 = 0, then $${\alpha ^{101}} + {\beta ^{107}}$$ is equal to :
    პასუხი
    (D)
    1
  • 4
    If the system of linear equations

    x + ky + 3z = 0
    3x + ky - 2z = 0
    2x + 4y - 3z = 0

    has a non-zero solution (x, y, z), then $${{xz} \over {{y^2}}}$$ is equal to
    პასუხი
    (C)
    10
  • 5
    If $$\left| {\matrix{ {x - 4} & {2x} & {2x} \cr {2x} & {x - 4} & {2x} \cr {2x} & {2x} & {x - 4} \cr } } \right| = \left( {A + Bx} \right){\left( {x - A} \right)^2}$$

    then the ordered pair (A, B) is equal to :
    პასუხი
    (D)
    (-4, 5)
  • 6
    Two sets A and B are as under :

    A = {($$a$$, b) $$ \in $$ R $$ \times $$ R : |$$a$$ - 5| < 1 and |b - 5| < 1};

    B = {($$a$$, b) $$ \in $$ R $$ \times $$ R : 4($$a$$ - 6)2 + 9(b - 5)2 $$ \le $$ 36 };

    Then
    პასუხი
    (C)
    A $$ \subset $$ B
  • 7
    Let $${a_1}$$, $${a_2}$$, $${a_3}$$, ......... ,$${a_{49}}$$ be in A.P. such that

    $$\sum\limits_{k = 0}^{12} {{a_{4k + 1}}} = 416$$ and $${a_9} + {a_{43}} = 66$$.

    $$a_1^2 + a_2^2 + ....... + a_{17}^2 = 140m$$, then m is equal to
    პასუხი
    (D)
    34
  • 8
    A bag contains 4 red and 6 black balls. A ball is drawn at random from the bag, its colour is observed and this ball along with two additional balls of the same colour are returned to the bag. If now a ball is drawn at random from the bag, then the probability that this drawn ball is red, is :
    პასუხი
    (C)
    $${2 \over 5}$$
  • 9
    If $$\sum\limits_{i = 1}^9 {\left( {{x_i} - 5} \right)} = 9$$ and

    $$\sum\limits_{i = 1}^9 {{{\left( {{x_i} - 5} \right)}^2}} = 45$$, then the standard deviation of the 9 items
    $${x_1},{x_2},.......,{x_9}$$ is
    პასუხი
    (D)
    2
  • 10
    Let $$\overrightarrow u $$ be a vector coplanar with the vectors $$\overrightarrow a = 2\widehat i + 3\widehat j - \widehat k$$ and $$\overrightarrow b = \widehat j + \widehat k$$. If $$\overrightarrow u $$ is perpendicular to $$\overrightarrow a $$ and $$\overrightarrow u .\overrightarrow b = 24$$, then $${\left| {\overrightarrow u } \right|^2}$$ is equal to
    პასუხი
    (A)
    336
  • 11
    A straight line through a fixed point (2, 3) intersects the coordinate axes at distinct points P and Q. If O is the origin and the rectangle OPRQ is completed, then the locus of R is :
    პასუხი
    (D)
    3x + 2y = xy
  • 12
    Let y = y(x) be the solution of the differential equation

    $$\sin x{{dy} \over {dx}} + y\cos x = 4x$$, $$x \in \left( {0,\pi } \right)$$.

    If $$y\left( {{\pi \over 2}} \right) = 0$$, then $$y\left( {{\pi \over 6}} \right)$$ is equal to :
    პასუხი
    (D)
    $$ - {8 \over 9}{\pi ^2}$$
  • 13
    The integral

    $$\int {{{{{\sin }^2}x{{\cos }^2}x} \over {{{\left( {{{\sin }^5}x + {{\cos }^3}x{{\sin }^2}x + {{\sin }^3}x{{\cos }^2}x + {{\cos }^5}x} \right)}^2}}}} dx$$

    is equal to
    პასუხი
    (C)
    $${{ - 1} \over {3\left( {1 + {{\tan }^3}x} \right)}} + C$$
  • 14
    The value of $$\int\limits_{ - \pi /2}^{\pi /2} {{{{{\sin }^2}x} \over {1 + {2^x}}}} dx$$ is
    პასუხი
    (A)
    $${\pi \over 4}$$
  • 15
    Let g(x) = cosx2, f(x) = $$\sqrt x $$ and $$\alpha ,\beta \left( {\alpha < \beta } \right)$$ be the roots of the quadratic equation 18x2 - 9$$\pi $$x + $${\pi ^2}$$ = 0. Then the area (in sq. units) bounded by the curve
    y = (gof)(x) and the lines $$x = \alpha $$, $$x = \beta $$ and y = 0 is :
    პასუხი
    (B)
    $${1 \over 2}\left( {\sqrt 3 - 1} \right)$$
  • 16
    Let S = { t $$ \in R:f(x) = \left| {x - \pi } \right|.\left( {{e^{\left| x \right|}} - 1} \right)$$$$\sin \left| x \right|$$ is not differentiable at t}, then the set S is equal to
    პასუხი
    (B)
    $$\phi $$ (an empty set)
  • 17
    Let $$f\left( x \right) = {x^2} + {1 \over {{x^2}}}$$ and $$g\left( x \right) = x - {1 \over x}$$,
    $$x \in R - \left\{ { - 1,0,1} \right\}$$.
    If $$h\left( x \right) = {{f\left( x \right)} \over {g\left( x \right)}}$$, then the local minimum value of h(x) is
    პასუხი
    (A)
    $$2\sqrt 2 $$
  • 18
    For each t $$ \in R$$, let [t] be the greatest integer less than or equal to t.

    Then $$\mathop {\lim }\limits_{x \to {0^ + }} x\left( {\left[ {{1 \over x}} \right] + \left[ {{2 \over x}} \right] + ..... + \left[ {{{15} \over x}} \right]} \right)$$
    პასუხი
    (D)
    is equal to 120