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Question Number 20036    Answers: 1   Comments: 0

Question Number 20031    Answers: 1   Comments: 0

Question Number 20035    Answers: 1   Comments: 1

In the following cases, find out the acceleration of the wedge and the block, if an external force F is applied as shown. (Both pulleys and strings are ideal)

$$\mathrm{In}\:\mathrm{the}\:\mathrm{following}\:\mathrm{cases},\:\mathrm{find}\:\mathrm{out}\:\mathrm{the} \\ $$$$\mathrm{acceleration}\:\mathrm{of}\:\mathrm{the}\:\mathrm{wedge}\:\mathrm{and}\:\mathrm{the}\:\mathrm{block}, \\ $$$$\mathrm{if}\:\mathrm{an}\:\mathrm{external}\:\mathrm{force}\:{F}\:\mathrm{is}\:\mathrm{applied}\:\mathrm{as} \\ $$$$\mathrm{shown}.\:\left(\mathrm{Both}\:\mathrm{pulleys}\:\mathrm{and}\:\mathrm{strings}\:\mathrm{are}\right. \\ $$$$\left.\mathrm{ideal}\right) \\ $$

Question Number 20051    Answers: 1   Comments: 0

If x ∈ R then ((x^2 + 2x + a)/(x^2 + 4x + 3a)) can take all real values if (1) a ∈ (0, 2) (2) a ∈ [0, 1] (3) a ∈ [−1, 1] (4) None of these

$$\mathrm{If}\:{x}\:\in\:{R}\:\mathrm{then}\:\frac{{x}^{\mathrm{2}} \:+\:\mathrm{2}{x}\:+\:{a}}{{x}^{\mathrm{2}} \:+\:\mathrm{4}{x}\:+\:\mathrm{3}{a}}\:\mathrm{can}\:\mathrm{take}\:\mathrm{all} \\ $$$$\mathrm{real}\:\mathrm{values}\:\mathrm{if} \\ $$$$\left(\mathrm{1}\right)\:{a}\:\in\:\left(\mathrm{0},\:\mathrm{2}\right) \\ $$$$\left(\mathrm{2}\right)\:{a}\:\in\:\left[\mathrm{0},\:\mathrm{1}\right] \\ $$$$\left(\mathrm{3}\right)\:{a}\:\in\:\left[−\mathrm{1},\:\mathrm{1}\right] \\ $$$$\left(\mathrm{4}\right)\:\mathrm{None}\:\mathrm{of}\:\mathrm{these} \\ $$

Question Number 20021    Answers: 1   Comments: 0

A person observes the angle of elevation of the peak of a hill from a station to be α. He walks c metres along a slope inclined at the angle β and finds the angle of elevation of the peak of the hill to be γ. Show that the height of the peak above the ground is ((c sin α sin (γ − β))/((sin γ − α))).

$$\mathrm{A}\:\mathrm{person}\:\mathrm{observes}\:\mathrm{the}\:\mathrm{angle}\:\mathrm{of}\:\mathrm{elevation} \\ $$$$\mathrm{of}\:\mathrm{the}\:\mathrm{peak}\:\mathrm{of}\:\mathrm{a}\:\mathrm{hill}\:\mathrm{from}\:\mathrm{a}\:\mathrm{station}\:\mathrm{to}\:\mathrm{be} \\ $$$$\alpha.\:\mathrm{He}\:\mathrm{walks}\:{c}\:\mathrm{metres}\:\mathrm{along}\:\mathrm{a}\:\mathrm{slope} \\ $$$$\mathrm{inclined}\:\mathrm{at}\:\mathrm{the}\:\mathrm{angle}\:\beta\:\mathrm{and}\:\mathrm{finds}\:\mathrm{the} \\ $$$$\mathrm{angle}\:\mathrm{of}\:\mathrm{elevation}\:\mathrm{of}\:\mathrm{the}\:\mathrm{peak}\:\mathrm{of}\:\mathrm{the} \\ $$$$\mathrm{hill}\:\mathrm{to}\:\mathrm{be}\:\gamma.\:\mathrm{Show}\:\mathrm{that}\:\mathrm{the}\:\mathrm{height}\:\mathrm{of}\:\mathrm{the} \\ $$$$\mathrm{peak}\:\mathrm{above}\:\mathrm{the}\:\mathrm{ground}\:\mathrm{is} \\ $$$$\frac{{c}\:\mathrm{sin}\:\alpha\:\mathrm{sin}\:\left(\gamma\:−\:\beta\right)}{\left(\mathrm{sin}\:\gamma\:−\:\alpha\right)}. \\ $$

Question Number 20019    Answers: 1   Comments: 0

In any triangle ABC, prove that a (cos C − cos B) = 2 (b − c) cos^2 (A/2)

$$\mathrm{In}\:\mathrm{any}\:\mathrm{triangle}\:{ABC},\:\mathrm{prove}\:\mathrm{that} \\ $$$${a}\:\left(\mathrm{cos}\:{C}\:−\:\mathrm{cos}\:{B}\right)\:=\:\mathrm{2}\:\left({b}\:−\:{c}\right)\:\mathrm{cos}^{\mathrm{2}} \:\frac{{A}}{\mathrm{2}} \\ $$

Question Number 20044    Answers: 2   Comments: 0

Question Number 20014    Answers: 0   Comments: 1

A person in lift is holding a water jar, which has a small hole at the lower end of its side. When the lift is at rest, the water jet coming out of the hole hits the floor of the lift at a distance d of 1.2 m from the person. In the following, state of the lift′s motion is given in List I and the distance where the water jet hits the floor of the lift is given in List II. Match the statements from List I with those in List II. List I P. Lift is accelerating vertically up Q. Lift is accelerating vertically down with an acceleration less than the gravitational acceleration R. Lift is moving vertically up with constant speed S. Lift is falling freely List II 1. d = 1.2 m 2. d > 1.2 m 3. d < 1.2 m 4. No water leaks out of the jar

$$\mathrm{A}\:\mathrm{person}\:\mathrm{in}\:\mathrm{lift}\:\mathrm{is}\:\mathrm{holding}\:\mathrm{a}\:\mathrm{water}\:\mathrm{jar}, \\ $$$$\mathrm{which}\:\mathrm{has}\:\mathrm{a}\:\mathrm{small}\:\mathrm{hole}\:\mathrm{at}\:\mathrm{the}\:\mathrm{lower}\:\mathrm{end} \\ $$$$\mathrm{of}\:\mathrm{its}\:\mathrm{side}.\:\mathrm{When}\:\mathrm{the}\:\mathrm{lift}\:\mathrm{is}\:\mathrm{at}\:\mathrm{rest},\:\mathrm{the} \\ $$$$\mathrm{water}\:\mathrm{jet}\:\mathrm{coming}\:\mathrm{out}\:\mathrm{of}\:\mathrm{the}\:\mathrm{hole}\:\mathrm{hits} \\ $$$$\mathrm{the}\:\mathrm{floor}\:\mathrm{of}\:\mathrm{the}\:\mathrm{lift}\:\mathrm{at}\:\mathrm{a}\:\mathrm{distance}\:{d}\:\mathrm{of} \\ $$$$\mathrm{1}.\mathrm{2}\:\mathrm{m}\:\mathrm{from}\:\mathrm{the}\:\mathrm{person}.\:\mathrm{In}\:\mathrm{the}\:\mathrm{following}, \\ $$$$\mathrm{state}\:\mathrm{of}\:\mathrm{the}\:\mathrm{lift}'\mathrm{s}\:\mathrm{motion}\:\mathrm{is}\:\mathrm{given}\:\mathrm{in}\:\mathrm{List} \\ $$$$\mathrm{I}\:\mathrm{and}\:\mathrm{the}\:\mathrm{distance}\:\mathrm{where}\:\mathrm{the}\:\mathrm{water}\:\mathrm{jet} \\ $$$$\mathrm{hits}\:\mathrm{the}\:\mathrm{floor}\:\mathrm{of}\:\mathrm{the}\:\mathrm{lift}\:\mathrm{is}\:\mathrm{given}\:\mathrm{in}\:\mathrm{List} \\ $$$$\mathrm{II}.\:\mathrm{Match}\:\mathrm{the}\:\mathrm{statements}\:\mathrm{from}\:\mathrm{List}\:\mathrm{I} \\ $$$$\mathrm{with}\:\mathrm{those}\:\mathrm{in}\:\mathrm{List}\:\mathrm{II}. \\ $$$$\boldsymbol{\mathrm{List}}\:\boldsymbol{\mathrm{I}} \\ $$$$\boldsymbol{\mathrm{P}}.\:\mathrm{Lift}\:\mathrm{is}\:\mathrm{accelerating}\:\mathrm{vertically}\:\mathrm{up} \\ $$$$\boldsymbol{\mathrm{Q}}.\:\mathrm{Lift}\:\mathrm{is}\:\mathrm{accelerating}\:\mathrm{vertically}\:\mathrm{down} \\ $$$$\mathrm{with}\:\mathrm{an}\:\mathrm{acceleration}\:\mathrm{less}\:\mathrm{than}\:\mathrm{the} \\ $$$$\mathrm{gravitational}\:\mathrm{acceleration} \\ $$$$\boldsymbol{\mathrm{R}}.\:\mathrm{Lift}\:\mathrm{is}\:\mathrm{moving}\:\mathrm{vertically}\:\mathrm{up}\:\mathrm{with} \\ $$$$\mathrm{constant}\:\mathrm{speed} \\ $$$$\boldsymbol{\mathrm{S}}.\:\mathrm{Lift}\:\mathrm{is}\:\mathrm{falling}\:\mathrm{freely} \\ $$$$\boldsymbol{\mathrm{List}}\:\boldsymbol{\mathrm{II}} \\ $$$$\mathrm{1}.\:{d}\:=\:\mathrm{1}.\mathrm{2}\:\mathrm{m} \\ $$$$\mathrm{2}.\:{d}\:>\:\mathrm{1}.\mathrm{2}\:\mathrm{m} \\ $$$$\mathrm{3}.\:{d}\:<\:\mathrm{1}.\mathrm{2}\:\mathrm{m} \\ $$$$\mathrm{4}.\:\mathrm{No}\:\mathrm{water}\:\mathrm{leaks}\:\mathrm{out}\:\mathrm{of}\:\mathrm{the}\:\mathrm{jar} \\ $$

Question Number 20013    Answers: 0   Comments: 4

Show that the equation (1/(x − a)) + (1/(x − b)) + (1/(x − c)) = 0 can have a pair of equal roots if a = b = c.

$$\mathrm{Show}\:\mathrm{that}\:\mathrm{the}\:\mathrm{equation}\:\frac{\mathrm{1}}{{x}\:−\:{a}}\:+\:\frac{\mathrm{1}}{{x}\:−\:{b}} \\ $$$$+\:\frac{\mathrm{1}}{{x}\:−\:{c}}\:=\:\mathrm{0}\:\mathrm{can}\:\mathrm{have}\:\mathrm{a}\:\mathrm{pair}\:\mathrm{of}\:\mathrm{equal} \\ $$$$\mathrm{roots}\:\mathrm{if}\:{a}\:=\:{b}\:=\:{c}. \\ $$

Question Number 20131    Answers: 1   Comments: 4

In rectangle ABCD,AB=8, BC=20.P is a point on AD so that ∠BPC=90°.If r_1 ,r_2 ,r_3 are the radii of the incircles of APB, BPC, and CPD. find r_1 +r_2 +r_3

$${In}\:{rectangle}\:{ABCD},{AB}=\mathrm{8}, \\ $$$${BC}=\mathrm{20}.{P}\:{is}\:{a}\:{point}\:{on}\:{AD}\:{so} \\ $$$${that}\:\angle{BPC}=\mathrm{90}°.{If}\:{r}_{\mathrm{1}} ,{r}_{\mathrm{2}} ,{r}_{\mathrm{3}} \:{are}\:{the} \\ $$$${radii}\:{of}\:{the}\:{incircles}\:{of}\:{APB}, \\ $$$${BPC},\:{and}\:{CPD}.\:{find}\:{r}_{\mathrm{1}} +{r}_{\mathrm{2}} +{r}_{\mathrm{3}} \\ $$

Question Number 20001    Answers: 1   Comments: 0

The number of the roots of the quadratic equation 8sec^2 θ − 6secθ + 1 = 0 is

$$\mathrm{The}\:\mathrm{number}\:\mathrm{of}\:\mathrm{the}\:\mathrm{roots}\:\mathrm{of}\:\mathrm{the}\:\mathrm{quadratic} \\ $$$$\mathrm{equation}\:\mathrm{8sec}^{\mathrm{2}} \theta\:−\:\mathrm{6sec}\theta\:+\:\mathrm{1}\:=\:\mathrm{0}\:\mathrm{is} \\ $$

Question Number 20045    Answers: 0   Comments: 0

Question Number 19986    Answers: 1   Comments: 0

An aeroplane has to go from a point A to point B, 500 km away due 30° east of north. A wind is blowing due north at a speed of 20 ms^(−1) . The air speed of the plane is 150 ms^(−1) . Find the direction in which the pilot should head the plane to reach point B.

$$\mathrm{An}\:\mathrm{aeroplane}\:\mathrm{has}\:\mathrm{to}\:\mathrm{go}\:\mathrm{from}\:\mathrm{a}\:\mathrm{point}\:{A} \\ $$$$\mathrm{to}\:\mathrm{point}\:{B},\:\mathrm{500}\:\mathrm{km}\:\mathrm{away}\:\mathrm{due}\:\mathrm{30}°\:\mathrm{east} \\ $$$$\mathrm{of}\:\mathrm{north}.\:\mathrm{A}\:\mathrm{wind}\:\mathrm{is}\:\mathrm{blowing}\:\mathrm{due}\:\mathrm{north} \\ $$$$\mathrm{at}\:\mathrm{a}\:\mathrm{speed}\:\mathrm{of}\:\mathrm{20}\:\mathrm{ms}^{−\mathrm{1}} .\:\mathrm{The}\:\mathrm{air}\:\mathrm{speed}\:\mathrm{of} \\ $$$$\mathrm{the}\:\mathrm{plane}\:\mathrm{is}\:\mathrm{150}\:\mathrm{ms}^{−\mathrm{1}} .\:\mathrm{Find}\:\mathrm{the}\:\mathrm{direction} \\ $$$$\mathrm{in}\:\mathrm{which}\:\mathrm{the}\:\mathrm{pilot}\:\mathrm{should}\:\mathrm{head}\:\mathrm{the} \\ $$$$\mathrm{plane}\:\mathrm{to}\:\mathrm{reach}\:\mathrm{point}\:{B}. \\ $$

Question Number 19982    Answers: 1   Comments: 1

What is the number of ordered pairs (A, B) where A and B are subsets of {1, 2, ..., 5} such that neither A ⊆ B nor B ⊆ A?

$$\mathrm{What}\:\mathrm{is}\:\mathrm{the}\:\mathrm{number}\:\mathrm{of}\:\mathrm{ordered}\:\mathrm{pairs} \\ $$$$\left({A},\:{B}\right)\:\mathrm{where}\:{A}\:\mathrm{and}\:{B}\:\mathrm{are}\:\mathrm{subsets}\:\mathrm{of} \\ $$$$\left\{\mathrm{1},\:\mathrm{2},\:...,\:\mathrm{5}\right\}\:\mathrm{such}\:\mathrm{that}\:\mathrm{neither}\:{A}\:\subseteq\:{B} \\ $$$$\mathrm{nor}\:{B}\:\subseteq\:{A}? \\ $$

Question Number 19970    Answers: 0   Comments: 4

The velocity-time graph of a body is shown in figure. The displacement covered by the body in 8 seconds is

$$\mathrm{The}\:\mathrm{velocity}-\mathrm{time}\:\mathrm{graph}\:\mathrm{of}\:\mathrm{a}\:\mathrm{body}\:\mathrm{is} \\ $$$$\mathrm{shown}\:\mathrm{in}\:\mathrm{figure}.\:\mathrm{The}\:\mathrm{displacement} \\ $$$$\mathrm{covered}\:\mathrm{by}\:\mathrm{the}\:\mathrm{body}\:\mathrm{in}\:\mathrm{8}\:\mathrm{seconds}\:\mathrm{is} \\ $$

Question Number 19976    Answers: 1   Comments: 0

Three vectors A^(→) , B^(→) and C^(→) add up to zero. Find which is false. (a) (A^(→) ×B^(→) )×C^(→) is not zero unless B^(→) , C^(→) are parallel (b) (A^(→) ×B^(→) )∙C^(→) is not zero unless B^(→) , C^(→) are parallel (c) If A^(→) , B^(→) , C^(→) define a plane, (A^(→) ×B^(→) ×C^(→) ) is in that plane (d) (A^(→) ×B^(→) ).C^(→) = ∣A^(→) ∣∣B^(→) ∣∣C^(→) ∣ → C^2 = A^2 + B^2

$$\mathrm{Three}\:\mathrm{vectors}\:\overset{\rightarrow} {{A}},\:\overset{\rightarrow} {{B}}\:\mathrm{and}\:\overset{\rightarrow} {{C}}\:\mathrm{add}\:\mathrm{up}\:\mathrm{to} \\ $$$$\mathrm{zero}.\:\mathrm{Find}\:\mathrm{which}\:\mathrm{is}\:\mathrm{false}. \\ $$$$\left({a}\right)\:\left(\overset{\rightarrow} {{A}}×\overset{\rightarrow} {{B}}\right)×\overset{\rightarrow} {{C}}\:\mathrm{is}\:\mathrm{not}\:\mathrm{zero}\:\mathrm{unless}\:\overset{\rightarrow} {{B}},\:\overset{\rightarrow} {{C}} \\ $$$$\mathrm{are}\:\mathrm{parallel} \\ $$$$\left({b}\right)\:\left(\overset{\rightarrow} {{A}}×\overset{\rightarrow} {{B}}\right)\centerdot\overset{\rightarrow} {{C}}\:\mathrm{is}\:\mathrm{not}\:\mathrm{zero}\:\mathrm{unless}\:\overset{\rightarrow} {{B}},\:\overset{\rightarrow} {{C}} \\ $$$$\mathrm{are}\:\mathrm{parallel} \\ $$$$\left({c}\right)\:\mathrm{If}\:\overset{\rightarrow} {{A}},\:\overset{\rightarrow} {{B}},\:\overset{\rightarrow} {{C}}\:\mathrm{define}\:\mathrm{a}\:\mathrm{plane},\:\left(\overset{\rightarrow} {{A}}×\overset{\rightarrow} {{B}}×\overset{\rightarrow} {{C}}\right) \\ $$$$\mathrm{is}\:\mathrm{in}\:\mathrm{that}\:\mathrm{plane} \\ $$$$\left({d}\right)\:\left(\overset{\rightarrow} {{A}}×\overset{\rightarrow} {{B}}\right).\overset{\rightarrow} {{C}}\:=\:\mid\overset{\rightarrow} {{A}}\mid\mid\overset{\rightarrow} {{B}}\mid\mid\overset{\rightarrow} {{C}}\mid\:\rightarrow\:{C}^{\mathrm{2}} \:=\:{A}^{\mathrm{2}} \:+\:{B}^{\mathrm{2}} \\ $$

Question Number 19964    Answers: 1   Comments: 1

Question Number 19955    Answers: 1   Comments: 2

Question Number 19948    Answers: 0   Comments: 0

Question Number 19945    Answers: 1   Comments: 0

If α and β are the roots of equation x^2 + px + q = 0 and α^2 , β^2 are roots of the equation x^2 − rx + s = 0, show that the equation x^2 − 4qx + 2q^2 − r = 0 has real roots.

$$\mathrm{If}\:\alpha\:\mathrm{and}\:\beta\:\mathrm{are}\:\mathrm{the}\:\mathrm{roots}\:\mathrm{of}\:\mathrm{equation} \\ $$$${x}^{\mathrm{2}} \:+\:{px}\:+\:{q}\:=\:\mathrm{0}\:\mathrm{and}\:\alpha^{\mathrm{2}} ,\:\beta^{\mathrm{2}} \:\mathrm{are}\:\mathrm{roots}\:\mathrm{of} \\ $$$$\mathrm{the}\:\mathrm{equation}\:{x}^{\mathrm{2}} \:−\:{rx}\:+\:{s}\:=\:\mathrm{0},\:\mathrm{show} \\ $$$$\mathrm{that}\:\mathrm{the}\:\mathrm{equation}\:{x}^{\mathrm{2}} \:−\:\mathrm{4}{qx}\:+\:\mathrm{2}{q}^{\mathrm{2}} \:−\:{r}\:=\:\mathrm{0} \\ $$$$\mathrm{has}\:\mathrm{real}\:\mathrm{roots}. \\ $$

Question Number 19940    Answers: 0   Comments: 2

A circle is inscribed in an isosceles trapezium. Prove that the ratio of the area of the circle to the area of the trapezium is equal to the ratio of the circum- ference of the circle to the perimeter of the trapezium.

$${A}\:{circle}\:{is}\:{inscribed}\:{in}\:{an} \\ $$$${isosceles}\:{trapezium}.\:{Prove}\:{that} \\ $$$${the}\:{ratio}\:{of}\:{the}\:{area}\:{of}\:{the}\:{circle} \\ $$$${to}\:{the}\:{area}\:{of}\:{the}\:{trapezium}\:{is} \\ $$$${equal}\:{to}\:{the}\:{ratio}\:{of}\:{the}\:{circum}- \\ $$$${ference}\:{of}\:{the}\:{circle}\:{to}\:{the}\: \\ $$$${perimeter}\:{of}\:{the}\:{trapezium}. \\ $$

Question Number 19939    Answers: 0   Comments: 0

f(x)=lnx

$${f}\left({x}\right)={lnx} \\ $$

Question Number 19936    Answers: 1   Comments: 1

Find the pricipal value of (1−i)^(1+i) .

$${Find}\:{the}\:{pricipal}\:{value}\:{of}\: \\ $$$$\:\:\:\:\:\left(\mathrm{1}−{i}\right)^{\mathrm{1}+{i}} \:. \\ $$

Question Number 19935    Answers: 0   Comments: 0

Which of the following points is a convex combination of (2, − 5, 0) and and (− 4, 2, 4) in R^3 (a) (0, 6, 1) (b) (− 4, − 2, 5) (c) (− 1, 0, 4) (d) (− 2, − (1/3), (8/3)) (e) None of the above

$$\mathrm{Which}\:\mathrm{of}\:\mathrm{the}\:\mathrm{following}\:\mathrm{points}\:\mathrm{is}\:\mathrm{a}\:\mathrm{convex}\:\mathrm{combination}\:\mathrm{of}\:\left(\mathrm{2},\:−\:\mathrm{5},\:\mathrm{0}\right)\:\mathrm{and} \\ $$$$\mathrm{and}\:\left(−\:\mathrm{4},\:\mathrm{2},\:\mathrm{4}\right)\:\mathrm{in}\:\mathbb{R}^{\mathrm{3}} \\ $$$$\left(\mathrm{a}\right)\:\:\left(\mathrm{0},\:\mathrm{6},\:\mathrm{1}\right) \\ $$$$\left(\mathrm{b}\right)\:\left(−\:\mathrm{4},\:−\:\mathrm{2},\:\mathrm{5}\right) \\ $$$$\left(\mathrm{c}\right)\:\left(−\:\mathrm{1},\:\mathrm{0},\:\mathrm{4}\right) \\ $$$$\left(\mathrm{d}\right)\:\left(−\:\mathrm{2},\:−\:\frac{\mathrm{1}}{\mathrm{3}},\:\frac{\mathrm{8}}{\mathrm{3}}\right) \\ $$$$\left(\mathrm{e}\right)\:\mathrm{None}\:\mathrm{of}\:\mathrm{the}\:\mathrm{above} \\ $$

Question Number 20132    Answers: 1   Comments: 0

Question Number 19953    Answers: 0   Comments: 0

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