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 :
    Відповідь
    (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
    Відповідь
    (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 :
    Відповідь
    (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
    Відповідь
    (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 :
    Відповідь
    (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
    Відповідь
    (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
    Відповідь
    (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 :
    Відповідь
    (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
    Відповідь
    (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
    Відповідь
    (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 :
    Відповідь
    (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 :
    Відповідь
    (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
    Відповідь
    (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
    Відповідь
    (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 :
    Відповідь
    (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
    Відповідь
    (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
    Відповідь
    (A)
    $$2\sqrt 2 $$
  • 18
    For each t $$ \in R$$, let [t] be the greatest integer less than or equal to t.

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