Recent questions tagged jun-2007

If $f(x)$ is a p.d.f of a normal distribution with mean $\mu$ then $\int\limits_{-\infty}^{\infty}f(x)dx$ is

asked Jun 3, 2013 by poojasapani_1

1 answer

In $16$ throws of a die getting an even number is considered a success. Then the variance of the successes is

asked May 28, 2013 by poojasapani_1

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Variance of the random variable $X$ is$4$ .Its mean is $2.$ Then $E(X^{2})$ is

asked May 28, 2013 by poojasapani_1

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In the multiplicative group of cube root of unity, the order of $w^{2}$ is

asked May 24, 2013 by poojasapani_1

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Which of the following is a tautology?

asked May 24, 2013 by poojasapani_1

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The differential equation of all circles with centre at the origin is

asked May 23, 2013 by poojasapani_1

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Integrating factor of $\large\frac{dy}{dx}+\frac{1}{x\log x}$$.y=\large\frac{2}{x^{2}}$ is

asked May 22, 2013 by poojasapani_1

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If $ \cos x $ is an integrating factor of the differential equation $\large\frac{dy}{dx}$$+Py=Q$ then $P$=

asked May 22, 2013 by poojasapani_1

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The volume of the solid obtained by revolving $\large\frac{x^{2}}{9}+\frac{y^{2}}{16}$$=1$ about the minor axis is

asked May 22, 2013 by poojasapani_1

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The area bounded by the line $y=x,$ the $x$-axis,the ordinates $x=1,x=2$ is

asked May 22, 2013 by poojasapani_1

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The value of $\int\limits_{-\pi/2}^{\pi/2}\large\left(\frac{\sin x}{2+\cos x}\right)$$dx$ is

asked May 21, 2013 by poojasapani_1

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If $u=y\sin x,$ then $\large\frac{\partial^{2} u}{\partial x\partial y}$ is equal to

asked May 21, 2013 by poojasapani_1

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An asymptote to the curve $y^{2}(a+2x)=x^{2}(3a-x)$ is

asked May 21, 2013 by poojasapani_1

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The radius of a cylinder is increasing at the rate of $2$ cm/sec and its altitude is decreasing at the rate of $3$cm/sec . The rate of change of volume when the radius is $3$cm and the altitude is $5$cm is

asked May 15, 2013 by poojasapani_1

1 answer

The angle between the curves $\large\frac{x^{2}}{25}+\frac{y^{2}}{9}=$$1$ and $\large\frac{x^{2}}{8}-\frac{y^{2}}{8}=$$1$ is

asked May 15, 2013 by poojasapani_1

1 answer

The slope of the normal to the curve $y=3x^{2}$ at the point whose $x$ coordinate is $2$ is

asked May 15, 2013 by poojasapani_1

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The eccentricity of the hyperbola whose latus rectum is equal to half of its conjugate axis is

asked May 14, 2013 by poojasapani_1

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The tangents at the end of any focal chord to the parabola $y^{2}=12x$ intersect on the line

asked May 13, 2013 by poojasapani_1

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The value of $i+i^{22}+i^{23}+i^{24}+i^{25}$ is

asked May 12, 2013 by poojasapani_1

1 answer

$\large\frac{1+e^{-i\theta}}{1+e^{i\theta}}$=

asked May 12, 2013 by poojasapani_1

1 answer

The modulus and amplitude of the complex number $[e^{3-i \pi/4}]^{3}$ is respectively

asked May 11, 2013 by poojasapani_1

1 answer

If$[\overrightarrow{a} + \overrightarrow{b},\overrightarrow{b}+\overrightarrow{c},\overrightarrow{c} + \overrightarrow{a}]=8$ then $[\overrightarrow{a},\overrightarrow{b},\overrightarrow{c}]$ is

asked May 10, 2013 by poojasapani_1

1 answer

If the projection of $\overrightarrow{a} $ on $\overrightarrow{b} $ and the projection of $\overrightarrow{b}$ on $\overrightarrow{a}$ are equal then the angle between $\overrightarrow{a}+\overrightarrow{b}$ and $\overrightarrow{a}-\overrightarrow{b}$ is

asked May 10, 2013 by poojasapani_1

1 answer

The vectors $\overrightarrow{2i}+\overrightarrow{3j}+\overrightarrow{4k} $ and $\overrightarrow{ai}+\overrightarrow{bj}+\overrightarrow{ck}$ are perpendicular when

asked May 9, 2013 by poojasapani_1

1 answer

If $\overrightarrow{a}$ and $\overrightarrow{b} $ include an angle $120^{\circ}$ and their magnitude are $2$ and $\sqrt{3}$ then $\overrightarrow{a} .\overrightarrow{b} $ is equal to

asked May 8, 2013 by poojasapani_1

1 answer

In a system of $3$ linear non-homogeneous equation with three unknowns,if $\bigtriangleup=0\;$ and $\;\bigtriangleup_{x}=0 ,\bigtriangleup_y\neq 0 $ and $ \bigtriangleup_z=0$ then the system has

asked May 7, 2013 by poojasapani_1

1 answer

If $A$=$\begin{bmatrix} 2 & 1 \\3 & 4 \end{bmatrix}$, than (adj $A)A$=

asked May 7, 2013 by poojasapani_1

1 answer

Find the intervals of concavity and the points of inflection of the following functions: $y=12x^{2}-2x^{3}-x^{4}$

asked May 6, 2013 by poojasapani_1

1 answer

Find the intervals on which $f$ is increasing or decreasing. $f(x)=20-x-x^{2}$

asked May 4, 2013 by poojasapani_1

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Find the area of the region bounded by the curve $y=3x^{2}-x$ and the $x$-axis between $x=-1$ and $x=1$

asked Apr 27, 2013 by poojasapani_1

1 answer

Trace the curve $y$=$x^{3}$ Discuss the following curves for extence,symmetry,Asymptotes and loops

asked Apr 24, 2013 by poojasapani_1

1 answer

Suppose that the amount of cosmic radiation to which a person is exposed when flying by jet across the united states is a random variable having a normal distribution with a mean of $4.35 m$ rem and standard deviation of $0.59m$ rem. What is the probability that a person will be exposed to than $5.20m$ rem of cosmic radiation of such flight.

asked Apr 22, 2013 by poojasapani_1

1 answer

In an entrance examination a student has to answer all the $120$ questions. Each question has four options and only one option is correct. A student gets $1$ mark for a correct answer and loses half mark for a wrong answer. What is the expectation of the mark scored by a student if he chooses the answer to each question at random?

asked Apr 20, 2013 by poojasapani_1

1 answer

The sum of Rs $1000$ is compounded continuously, the nominal rate of interest being four percent per annum. In how many years will the amount be twice the original principal ? $(\log_{e}$$2=0.6931)$

asked Apr 17, 2013 by poojasapani_1

1 answer

Solve the following $(x^{2}+y^{2})\;dy$ =$ xy \;dx$

asked Apr 15, 2013 by poojasapani_1

1 answer

Find the equation of rectangular hyperbola which has for one of its asymptotes the line $x+2y-5=0 $ and passes through the point $(6 , 0 ) $ and $(-3 , 0 )$ find its equation and asymptotes

asked Apr 13, 2013 by poojasapani_1

1 answer

A satellite is travelling around the earth in an elliptical orbit having the earth heat a focus and of eccentricity $\large\frac{1}{2}.$ The shortest distance that the satellite get to the earth is $400kms.$ Find the longest distance that the satellite gets from the earth.

asked Apr 11, 2013 by poojasapani_1

1 answer

Show that the following two lines are skew lines: $\overrightarrow{r}=(\overrightarrow{3i}+\overrightarrow{5j}+\overrightarrow{7k})+ t (\overrightarrow{i}-\overrightarrow{2j}+\overrightarrow{k})$ and $\overrightarrow{r}=(\overrightarrow{i}+\overrightarrow{j}+\overrightarrow{k}) + s (\overrightarrow{7i}-\overrightarrow{6j}+\overrightarrow{7k})$

asked Apr 7, 2013 by poojasapani_1

1 answer

Prove that sin $(A - B)$= sin $ A$ cos $B$ - cos $A$ sin $B$.

asked Apr 5, 2013 by poojasapani_1

1 answer

Discuss the solutions of the system of equations for all values of $\lambda$. $ x+y+z=2\;,2x+y-2z=2\;,\lambda\;x+y+4z=2$

asked Apr 2, 2013 by poojasapani_1

1 answer

Solve by matrix inversion method following system of linear equation:$\;2x\;-\;y\;=7\;,\;3x\;-2y\;=11$

asked Mar 29, 2013 by poojasapani_1

1 answer

Show that the set G of all rational numbers except − 1 forms an abelian group with respect to the operation $$ given by $a b = a + b + ab$ for all $a, b \in G$.

asked Nov 27, 2012 by balaji.thirumalai

1 answer

Show that p ↔ q ≡ ((∼ p) ∨ q) ∧ ((∼ q) ∨ p)

asked Nov 27, 2012 by balaji.thirumalai

1 answer

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