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

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