If $x_1, x_2,\ldots , x_n$ and $\frac{1}{h_1}, \frac{1}{h_2},\ldots , \frac{1}{h_n}$ are two A.P.s such that
$x_3 = h_2 = 8$ and $x_8 = h_7 = 20$, then $x_5 \cdot h_{10}$ equals :
If $\lambda \in \mathbb{R}$ is such that the sum of the cubes of the roots of the equation $x^{2} + (2-\lambda)x + (10-\lambda)=0$ is minimum, then the magnitude of the difference of the roots of this equation is :
The set of all $\alpha \in \mathbb{R}$ for which $w = \dfrac{1 + (1-8\alpha)z}{1-z}$ is purely imaginary number, for all $z \in \mathbb{C}$ satisfying $|z| = 1$ and $\operatorname{Re} z \ne 1$, is :
If the tangents drawn to the hyperbola $4y^{2}=x^{2}+1$ intersect the co-ordinate axes at the distinct points $A$ and $B$ then the locus of the mid point of $AB$ is :
If $\tan A$ and $\tan B$ are the roots of the quadratic equation $3x^{2}-10x-25=0$, then the value of
$3\sin^{2}(A+B)-10\sin(A+B)\cos(A+B)-25\cos^{2}(A+B)$ is :
A box $A$ contains $2$ white, $3$ red and $2$ black balls. Another box $B$ contains $4$ white, $2$ red and $3$ black balls. If two balls are drawn at random, without replacement, from a randomly selected box and one ball turns out to be white while the other ball turns out to be red, then the probability that both balls are drawn from box $B$ is :
The mean of set of $30$ observations is $75$. If each observation is multiplied by a non-zero number $\lambda$ and then each of them is decreased by $25$, their mean remains the same. Then $\lambda$ is equal to :
If $\overrightarrow a ,\,\,\overrightarrow b ,$ and $\overrightarrow C $ are unit vectors such that $\overrightarrow a + 2\overrightarrow b + 2\overrightarrow c = \overrightarrow 0 ,$ then $\left| {\overrightarrow a \times \overrightarrow c } \right|$ is equal to :
If a right circular cone, having maximum volume, is inscribed in a sphere of radius $3\ \text{cm}$, then the curved surface area (in $\text{cm}^{2}$) of this cone is :
If $f\left( {{{x - 4} \over {x + 2}}} \right) = 2x + 1,$ (x $ \in $ R $-${1, $-$ 2}), then $\int f \left( x \right)dx$ is equal to :
(where C is a constant of integration)
Let $S={(\lambda,\mu)\in\mathbb{R}\times\mathbb{R}: f(t)=(\lvert\lambda\rvert e^{\lvert t\rvert}-\mu)\cdot\sin(2\lvert t\rvert),\ t\in\mathbb{R},\text{ is a differentiable function}}$. Then $S$ is a subset of :
If $a$, $b$, $c$ are in A.P. and $a^{2}$, $b^{2}$, $c^{2}$ are in G.P. such that $a < b < c$ and $a + b + c = \dfrac{3}{4}$, then the value of $a$ is :
Suppose $A$ is any $3\times 3$ non-singular matrix and $(A-3I)(A-5I)=0$ where $I=I_{3}$ and $O=O_{3}$. If $\alpha A+\beta A^{-1}=4I$, then $\alpha+\beta$ is equal to :
If the position vectors of the vertices $A$, $B$ and $C$ of a $\triangle ABC$ are respectively $4\hat{i}+7\hat{j}+8\hat{k}$, $2\hat{i}+3\hat{j}+4\hat{k}$ and $2\hat{i}+5\hat{j}+7\hat{k}$, then the position vector of the point where the bisector of $\angle A$ meets $BC$ is :
A player $X$ has a biased coin whose probability of showing heads is $p$ and a player $Y$ has a fair coin. They start playing a game with their own coins and play alternately. The player who throws a head first is a winner. If $X$ starts the game, and the probability of winning the game by both the players is equal, then the value of $p$ is :
Tangents drawn from the point $(-8,0)$ to the parabola $y^{2} = 8x$ touch the parabola at $P$ and $Q$. If $F$ is the focus of the parabola, then the area of the triangle $PFQ$ (in sq. units) is equal to :
The foot of the perpendicular drawn from the origin, on the line, $3x + y = \lambda\ (\lambda \ne 0)$ is $P$. If the line meets $x$-axis at $A$ and $y$-axis at $B$, then the ratio $BP : PA$ is :
The sides of a rhombus $ABCD$ are parallel to the lines, $x - y + 2 = 0$ and $7x - y + 3 = 0$. If the diagonals of the rhombus intersect $P(1,2)$ and the vertex $A$ (different from the origin) is on the $y$-axis, then the coordinate of $A$ is :
If $\displaystyle \int \frac{2x+5}{\sqrt{7-6x-x^{2}}},dx = A\sqrt{7-6x-x^{2}} + B\sin^{-1}!\left(\frac{x+3}{4}\right) + C$
(where $C$ is a constant of integration), then the ordered pair $(A,B)$ is equal to :
If $I_1=\displaystyle\int_{0}^{1} e^{-x}\cos^{2}x,dx$;
$I_2=\displaystyle\int_{0}^{1} e^{-x^{2}}\cos^{2}x,dx$ and
$I_3=\displaystyle\int_{0}^{1} e^{-x^{3}},dx$; then
Let $f(x)$ be a polynomial of degree $4$ having extreme values at $x=1$ and $x=2$.
If $\lim_{x\to 0}\left(\dfrac{f(x)}{x^{2}}+1\right)=3$ then $f(-1)$ is equal to :
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 :
Let $a_1, a_2, a_3, \ldots, a_{49}$ be in A.P. such that
$\displaystyle \sum_{k=0}^{12} a_{4k+1} = 416$ and $a_9 + a_{43} = 66$.
If $a_1^{2} + a_2^{2} + \cdots + a_{17}^{2} = 140m$, then $m$ is equal to :
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 :
If $\displaystyle \sum_{i=1}^{9}(x_i-5)=9$ and $\displaystyle \sum_{i=1}^{9}(x_i-5)^{2}=45$, then the standard deviation of the $9$ items $x_1,x_2,\ldots,x_9$ is :
Let $\vec{u}$ be a vector coplanar with the vectors $\vec{a}=2\hat{i}+3\hat{j}-\hat{k}$ and $\vec{b}=\hat{j}+\hat{k}$. If $\vec{u}$ is perpendicular to $\vec{a}$ and $\vec{u}\cdot\vec{b}=24$, then $\lvert\vec{u}\rvert^{2}$ is equal to :
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 :
Let $y = y(x)$ be the solution of the differential equation
$\sin x \dfrac{dy}{dx} + y \cos x = 4x,\ x \in (0,\pi).$
If $y\left(\dfrac{\pi}{2}\right) = 0$, then $y\left(\dfrac{\pi}{6}\right)$ is equal to :
The integral
$\displaystyle \int \frac{\sin^{2}x \cos^{2}x}{\left(\sin^{5}x + \cos^{3}x \sin^{2}x + \sin^{3}x \cos^{2}x + \cos^{5}x\right)^{2}},dx$
is equal to :
Let $g(x)=\cos x^{2}$, $f(x)=\sqrt{x}$ and $\alpha,\beta\ (\alpha<\beta)$ be the roots of the quadratic equation $18x^{2}-9\pi x+\pi^{2}=0$. Then the area (in sq. units) bounded by the curve $y=(g\circ f)(x)$ and the lines $x=\alpha$, $x=\beta$ and $y=0$ is :
Let $f(x) = x^{2} + \dfrac{1}{x^{2}}$ and $g(x) = x - \dfrac{1}{x}$, $x \in \mathbb{R} - {-1,0,1}$.
If $h(x) = \dfrac{f(x)}{g(x)}$, then the local minimum value of $h(x)$ is
For each $t \in \mathbb{R}$, let $[t]$ be the greatest integer less than or equal to $t$.
Then $\displaystyle \lim_{x \to 0^{+}} x\left(\left[\frac{1}{x}\right] + \left[\frac{2}{x}\right] + \cdots + \left[\frac{15}{x}\right]\right)$
If $\displaystyle \int \frac{\tan x}{1+\tan x+\tan^{2}x},dx = x - \frac{K}{\sqrt{A}}\tan^{-1}\left(\frac{K\tan x + 1}{\sqrt{A}}\right) + C,\ (C\ \text{is a constant of integration})$ then the ordered pair $(K,A)$ is equal to :
Let A = $\left[ {\matrix{
1 & 0 & 0 \cr
1 & 1 & 0 \cr
1 & 1 & 1 \cr
} } \right]$ and B = A20. Then the sum of the elements of the first column of B is :
If the function $f$ defined as
$f(x) = \dfrac{1}{x} - \dfrac{kx - 1}{e^{2x} - 1}, ; x \ne 0$,
is continuous at $x = 0$, then the ordered pair $(k, f(0))$ is equal to :
Let $M$ and $m$ be respectively the absolute maximum and the absolute minimum values of the function
$f(x) = 2x^{3} - 9x^{2} + 12x + 5$ in the interval $[0, 3]$. Then $M - m$ is equal to :
Let $\dfrac{1}{x_1},\dfrac{1}{x_2},\ldots,\dfrac{1}{x_n}$ $(x_i\ne0\text{ for }i=1,2,\ldots,n)$ be in A.P. such that $x_1=4$ and $x_{21}=20$. If $n$ is the least positive integer for which $x_n>50$, then $\displaystyle\sum_{i=1}^n \left(\dfrac{1}{x_i}\right)$ is equal to :
The number of numbers between $2000$ and $5000$ that can be formed with the digits $0,1,2,3,4$ (repetition of digits is not allowed) and are multiples of $3$ is :
If $\displaystyle \int \frac{\tan x}{1+\tan x+\tan^2 x},dx = x - \frac{K}{\sqrt{A}}\tan^{-1}!\left(\frac{K\tan x + 1}{\sqrt{A}}\right) + C,\ (C\text{ is a constant of integration})$ then the ordered pair $(K,A)$ is equal to :
Let $M$ and $m$ be respectively the absolute maximum and the absolute minimum values of the function $f(x)=2x^{3}-9x^{2}+12x+5$ in the interval $[0,3]$. Then $M-m$ is equal to :
If the function $f$ defined as $f(x)=\dfrac{1}{x}-\dfrac{kx-1}{e^{2x}-1},\ x\ne0$, is continuous at $x=0$, then the ordered pair $(k,f(0))$ is equal to :
Let $p, q$ and $r$ be real numbers $(p \ne q,, r \ne 0)$, such that the roots of the equation
$\dfrac{1}{x+p} + \dfrac{1}{x+q} = \dfrac{1}{r}$
are equal in magnitude but opposite in sign, then the sum of squares of these roots is equal to:
Let $\mathbb{N}$ denote the set of all natural numbers. Define two binary relations on $\mathbb{N}$ as
$R_1 = {(x,y) \in \mathbb{N} \times \mathbb{N} : 2x + y = 10}$ and
$R_2 = {(x,y) \in \mathbb{N} \times \mathbb{N} : x + 2y = 10}$. Then:
Two different families $A$ and $B$ are blessed with equal number of children. There are $3$ tickets to be distributed amongst the children of these families so that no child gets more than one ticket. If the probability that all the tickets go to the children of the family $B$ is $\dfrac{1}{12}$, then the number of children in each family is:
The mean and the standard deviation (s.d.) of five observations are $9$ and $0$, respectively. If one of the observations is changed such that the mean of the new set of five observations becomes $10$, then their s.d. is:
Let A, B and C be three events, which are pair-wise independent and $\overrightarrow E $ denotes the completement of an event E. If $P\left( {A \cap B \cap C} \right) = 0$ and $P\left( C \right) > 0,$ then $P\left[ {\left( {\overline A \cap \overline B } \right)\left| C \right.} \right]$ is equal to :
Let
$\vec{a} = \hat{i} + \hat{j} + \hat{k}$,
$\vec{c} = \hat{j} - \hat{k}$,
and a vector $\vec{b}$ be such that
$\vec{a} \times \vec{b} = \vec{c}$
and
$\vec{a} \cdot \vec{b} = 3$.
Then $|\vec{b}|$ equals:
If the angle between the lines $\dfrac{x}{2}=\dfrac{y}{2}=\dfrac{z}{1}$ and $\dfrac{5-x}{-2}=\dfrac{7y-14}{p}=\dfrac{z-3}{4}$ is $\cos^{-1}\left(\dfrac{2}{3}\right)$, then $p$ is equal to :
If the length of the latus rectum of an ellipse is $4$ units and the distance between a focus an its nearest vertex on the major axis is $\dfrac{3}{2}$ units, then its eccentricity is :
The locus of the point of intersection of the lines $ \sqrt{2}x - y + 4\sqrt{2}k = 0$ and $\sqrt{2}kx + ky - 4\sqrt{2} = 0$ $(k$ is any non-zero real parameter$)$, is :
If a circle $C$, whose radius is $3$, touches externally the circle $x^{2}+y^{2}+2x-4y-4=0$ at the point $(2,2)$, then the length of the intercept cut by this circle $C$ on the $x$-axis is equal to :
A $2,\text{m}$ ladder leans against a vertical wall. If the top of the ladder begins to slide down the wall at the rate of $25,\text{cm/sec}$, then the rate (in $\text{cm/sec}$) at which the bottom of the ladder slides away from the wall on the horizontal ground when the top of the ladder is $1,\text{m}$ above the ground is: