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Question Number 75104 Answers: 1 Comments: 0

Question Number 75102 Answers: 0 Comments: 0

show by integration that the centroid of a semi−circular lamina of radius a from the centre is ((4a)/(3π)).

$$\mathrm{show}\:\mathrm{by}\:\mathrm{integration}\:\mathrm{that}\:\mathrm{the}\:\mathrm{centroid} \\ $$$$\mathrm{of}\:\mathrm{a}\:\mathrm{semi}−\mathrm{circular}\:\mathrm{lamina}\:\mathrm{of}\:\mathrm{radius}\:{a}\: \\ $$$$\mathrm{from}\:\mathrm{the}\:\mathrm{centre}\:\mathrm{is}\:\:\:\frac{\mathrm{4}{a}}{\mathrm{3}\pi}. \\ $$

Question Number 75101 Answers: 4 Comments: 2

the vector equations of two lines L_1 and L_2 is given by L_1 :r= i−j+3k + λ(i−j +k) L_2 : r= 2i+aj + 6k + μ(2i + j + 3k) where a,λ,μ are real constants. given that L_1 and L_2 intersect find a. the value of the constant a. b. the position vector of the point of intersection between L_1 and L_2 c. the cosine of the acute angle between L_1 and L_2 please help

$${the}\:{vector}\:{equations}\:{of}\:{two}\:{lines}\:{L}_{\mathrm{1}} \:{and}\:{L}_{\mathrm{2}} \:{is}\:{given}\:{by} \\ $$$$\:{L}_{\mathrm{1}} :{r}=\:\boldsymbol{{i}}−\boldsymbol{{j}}+\mathrm{3}\boldsymbol{{k}}\:+\:\lambda\left(\boldsymbol{{i}}−\boldsymbol{{j}}\:+\boldsymbol{{k}}\right) \\ $$$${L}_{\mathrm{2}} \::\:{r}=\:\mathrm{2}\boldsymbol{{i}}+{a}\boldsymbol{{j}}\:+\:\mathrm{6}\boldsymbol{{k}}\:+\:\mu\left(\mathrm{2}\boldsymbol{{i}}\:+\:\boldsymbol{{j}}\:+\:\mathrm{3}\boldsymbol{{k}}\right) \\ $$$${where}\:{a},\lambda,\mu\:{are}\:{real}\:{constants}. \\ $$$${given}\:{that}\:{L}_{\mathrm{1}} \:{and}\:{L}_{\mathrm{2}} \:{intersect}\:{find} \\ $$$${a}.\:\:{the}\:{value}\:{of}\:{the}\:{constant}\:{a}. \\ $$$${b}.\:\:{the}\:{position}\:{vector}\:{of}\:{the}\:{point}\:{of}\: \\ $$$${intersection}\:{between}\:{L}_{\mathrm{1}} \:{and}\:{L}_{\mathrm{2}} \\ $$$${c}.\:{the}\:{cosine}\:{of}\:{the}\:{acute}\:{angle}\:{between}\:{L}_{\mathrm{1}} \:{and}\:{L}_{\mathrm{2}} \\ $$$${please}\:{help} \\ $$$$ \\ $$

Question Number 75100 Answers: 2 Comments: 0

find the intervals cor which the function h(x) = x^3 −3x is a) strickly increasing b) strickly decreasing

$$\:{find}\:{the}\:{intervals}\:{cor}\:{which}\:{the}\:{function} \\ $$$${h}\left({x}\right)\:=\:{x}^{\mathrm{3}} −\mathrm{3}{x}\:{is} \\ $$$$\left.{a}\right)\:{strickly}\:{increasing} \\ $$$$\left.{b}\right)\:{strickly}\:{decreasing} \\ $$$$ \\ $$

Question Number 75099 Answers: 1 Comments: 4

Given the matrix A = ((1,(−1),1),(0,2,( −1)),(2,3,0) ) and B= ((3,3,(−1)),((−2),(−2),1),((−4),(−5),2) ) find the matrix product AB and BA state the relationship between A and B find also the matrix product BM, where M= ((8),((−7)),(1) ) Hence solve the system of equations: x−y + z = 8, 2y −z =−7, 2x + 3y = 1.

$${Given}\:{the}\:{matrix}\: \\ $$$${A}\:=\:\begin{pmatrix}{\mathrm{1}}&{−\mathrm{1}}&{\mathrm{1}}\\{\mathrm{0}}&{\mathrm{2}}&{\:−\mathrm{1}}\\{\mathrm{2}}&{\mathrm{3}}&{\mathrm{0}}\end{pmatrix}\:\:{and}\:{B}=\:\begin{pmatrix}{\mathrm{3}}&{\mathrm{3}}&{−\mathrm{1}}\\{−\mathrm{2}}&{−\mathrm{2}}&{\mathrm{1}}\\{−\mathrm{4}}&{−\mathrm{5}}&{\mathrm{2}}\end{pmatrix} \\ $$$${find}\:{the}\:{matrix}\:{product}\:{AB}\:{and}\:{BA} \\ $$$${state}\:{the}\:{relationship}\:{between}\:{A}\:{and}\:{B} \\ $$$${find}\:{also}\:{the}\:{matrix}\:{product}\:{BM},\:{where}\:{M}=\begin{pmatrix}{\mathrm{8}}\\{−\mathrm{7}}\\{\mathrm{1}}\end{pmatrix} \\ $$$${Hence}\:{solve}\:{the}\:{system}\:{of}\:{equations}: \\ $$$$\:\:{x}−{y}\:+\:{z}\:=\:\mathrm{8}, \\ $$$$\:\:\:\:\:\:\:\mathrm{2}{y}\:−{z}\:=−\mathrm{7}, \\ $$$$\:\:\mathrm{2}{x}\:+\:\mathrm{3}{y}\:=\:\mathrm{1}. \\ $$

Question Number 75098 Answers: 1 Comments: 0

the function f is defined by f(x) = (2/(x^2 −1)) a) Express f into partial fraction b.show that ∫_3 ^5 f(x) dx = ln((4/3))

$$\mathrm{the}\:\mathrm{function}\:\mathrm{f}\:\mathrm{is}\:\mathrm{defined}\:\mathrm{by}\:{f}\left({x}\right)\:=\:\frac{\mathrm{2}}{{x}^{\mathrm{2}} −\mathrm{1}} \\ $$$$\left.{a}\right)\:\mathrm{Express}\:\mathrm{f}\:\mathrm{into}\:\mathrm{partial}\:\mathrm{fraction} \\ $$$$\mathrm{b}.\mathrm{show}\:\mathrm{that}\:\int_{\mathrm{3}} ^{\mathrm{5}} {f}\left({x}\right)\:{dx}\:=\:{ln}\left(\frac{\mathrm{4}}{\mathrm{3}}\right) \\ $$

Question Number 75093 Answers: 1 Comments: 1

∫cos^3 xsin^3 xdx

$$\int{cos}^{\mathrm{3}} {xsin}^{\mathrm{3}} {xdx} \\ $$

Question Number 75083 Answers: 1 Comments: 0

A function f is given by f(x) = { ((x^2 −3, 0≤x<2)),((4x−7, 2≤x<4)) :} is such that f(x) = f(x + 4) find f(27) and f(−106).

$${A}\:{function}\:{f}\:{is}\:{given}\:{by}\: \\ $$$$\:{f}\left({x}\right)\:=\:\begin{cases}{{x}^{\mathrm{2}} −\mathrm{3},\:\:\mathrm{0}\leqslant{x}<\mathrm{2}}\\{\mathrm{4}{x}−\mathrm{7},\:\mathrm{2}\leqslant{x}<\mathrm{4}}\end{cases} \\ $$$${is}\:{such}\:{that}\:{f}\left({x}\right)\:=\:{f}\left({x}\:+\:\mathrm{4}\right)\: \\ $$$${find}\:\:{f}\left(\mathrm{27}\right)\:{and}\:{f}\left(−\mathrm{106}\right). \\ $$

Question Number 75082 Answers: 1 Comments: 0

find ∫_0 ^π e^(cosx) sinx dx

$${find} \\ $$$$\int_{\mathrm{0}} ^{\pi} {e}^{{cosx}} {sinx}\:{dx} \\ $$

Question Number 75081 Answers: 1 Comments: 0

Evaluate ∫_1 ^(3 ) (x^2 /(1+x)) dx

$${Evaluate}\: \\ $$$$\:\int_{\mathrm{1}} ^{\mathrm{3}\:} \frac{{x}^{\mathrm{2}} }{\mathrm{1}+{x}}\:{dx} \\ $$

Question Number 75080 Answers: 0 Comments: 1

Find out A=Σ_(n=0) ^∞ ∫_0 ^(π/2) (1−(√(sinx)))^n cosxdx

$$\mathrm{Find}\:\mathrm{out}\: \\ $$$$\mathrm{A}=\underset{\mathrm{n}=\mathrm{0}} {\overset{\infty} {\sum}}\int_{\mathrm{0}} ^{\frac{\pi}{\mathrm{2}}} \left(\mathrm{1}−\sqrt{\mathrm{sinx}}\right)^{\mathrm{n}} \mathrm{cosxdx} \\ $$

Question Number 75079 Answers: 0 Comments: 0

Let f∈C([0,1],[0,1]) Prove that lim_(n→∞) ∫_([0,1]^n ) f((1/n)Σ_(i=1) ^n x_i )dx_1 ....dx_n =f((1/2))

$$\mathrm{Let}\:\mathrm{f}\in\mathrm{C}\left(\left[\mathrm{0},\mathrm{1}\right],\left[\mathrm{0},\mathrm{1}\right]\right)\:\: \\ $$$$\mathrm{Prove}\:\mathrm{that}\:\underset{\mathrm{n}\rightarrow\infty} {\mathrm{lim}}\:\:\int_{\left[\mathrm{0},\mathrm{1}\right]^{\mathrm{n}} } \mathrm{f}\left(\frac{\mathrm{1}}{\mathrm{n}}\underset{\mathrm{i}=\mathrm{1}} {\overset{\mathrm{n}} {\sum}}\mathrm{x}_{\mathrm{i}} \:\right)\mathrm{dx}_{\mathrm{1}} ....\mathrm{dx}_{\mathrm{n}} \:=\mathrm{f}\left(\frac{\mathrm{1}}{\mathrm{2}}\right) \\ $$

Question Number 75078 Answers: 1 Comments: 0

Question Number 75066 Answers: 1 Comments: 0

Prove that if f is a function R→R and there exist x_0 >0 , such as L(f)(x_0 ) exist then lim_(t→∞) f(t)e^(−x_0 t) =0 and ∀ x>x_0 L(f)(x) exist. L(f) is the Laplace transformed function

$$\mathrm{Prove}\:\:\mathrm{that}\:\mathrm{if}\:\:\mathrm{f}\:\mathrm{is}\:\mathrm{a}\:\mathrm{function}\:\mathbb{R}\rightarrow\mathbb{R}\: \\ $$$$\mathrm{and}\:\:\mathrm{there}\:\mathrm{exist}\:\mathrm{x}_{\mathrm{0}} >\mathrm{0}\:\:,\:\mathrm{such}\:\mathrm{as}\:\:\mathrm{L}\left(\mathrm{f}\right)\left(\mathrm{x}_{\mathrm{0}} \right)\:\mathrm{exist}\: \\ $$$$\mathrm{then}\:\underset{\mathrm{t}\rightarrow\infty} {\mathrm{lim}}\:\mathrm{f}\left(\mathrm{t}\right)\mathrm{e}^{−\mathrm{x}_{\mathrm{0}} \mathrm{t}} =\mathrm{0}\:\mathrm{and}\:\forall\:\mathrm{x}>\mathrm{x}_{\mathrm{0}} \:\:\mathrm{L}\left(\mathrm{f}\right)\left(\mathrm{x}\right)\:\mathrm{exist}. \\ $$$$\mathrm{L}\left(\mathrm{f}\right)\:\mathrm{is}\:\mathrm{the}\:\mathrm{Laplace}\:\mathrm{transformed}\:\mathrm{function} \\ $$

Question Number 75063 Answers: 1 Comments: 1

calculate Σ_(n=1) ^(17) (((−1)^n )/n^3 )

$${calculate}\:\:\sum_{{n}=\mathrm{1}} ^{\mathrm{17}} \:\:\frac{\left(−\mathrm{1}\right)^{{n}} }{{n}^{\mathrm{3}} } \\ $$

Question Number 75059 Answers: 0 Comments: 0

Question Number 75058 Answers: 1 Comments: 2

in triangle: ABC: a=(√(2 )),b−c=(((√2)+1)/2),B^ −C^ =(𝛑/2) find: h_a , S_(ABC ) ,d_(a ) , R ,A^ .

$$\boldsymbol{\mathrm{in}}\:\boldsymbol{\mathrm{triangle}}:\:\:\boldsymbol{\mathrm{ABC}}: \\ $$$$\boldsymbol{\mathrm{a}}=\sqrt{\mathrm{2}\:},\boldsymbol{\mathrm{b}}−\boldsymbol{\mathrm{c}}=\frac{\sqrt{\mathrm{2}}+\mathrm{1}}{\mathrm{2}},\overset{} {\boldsymbol{\mathrm{B}}}−\overset{} {\boldsymbol{\mathrm{C}}}=\frac{\boldsymbol{\pi}}{\mathrm{2}} \\ $$$$\boldsymbol{\mathrm{find}}:\:\:\boldsymbol{\mathrm{h}}_{\boldsymbol{\mathrm{a}}} ,\:\:\boldsymbol{\mathrm{S}}_{\boldsymbol{\mathrm{ABC}}\:\:} ,\boldsymbol{\mathrm{d}}_{\boldsymbol{\mathrm{a}}\:\:\:} ,\:\boldsymbol{\mathrm{R}}\:\:\:\:,\overset{} {\boldsymbol{\mathrm{A}}}. \\ $$

Question Number 75048 Answers: 1 Comments: 1

I would like that you help me to show this equality: 16cos (Π/(24))cos((5Π)/(24))cos((7Π)/(24))cos((11Π)/(24))=1

$$\mathrm{I}\:\mathrm{would}\:\mathrm{like}\:\mathrm{that}\:\mathrm{you}\:\mathrm{help}\:\mathrm{me}\:\mathrm{to}\: \\ $$$$\mathrm{show}\:\mathrm{this}\:\mathrm{equality}: \\ $$$$\mathrm{16cos}\:\frac{\Pi}{\mathrm{24}}\mathrm{cos}\frac{\mathrm{5}\Pi}{\mathrm{24}}\mathrm{cos}\frac{\mathrm{7}\Pi}{\mathrm{24}}\mathrm{cos}\frac{\mathrm{11}\Pi}{\mathrm{24}}=\mathrm{1} \\ $$

Question Number 75046 Answers: 0 Comments: 3

Question Number 75041 Answers: 1 Comments: 1

1) Show that for a∈]01]the function f_a :R_+ →R defined by f_a (x)=x^a is a−holder function in other way there exist K>0 such as ∀ x,y>0 ∣f_a (x)−f_a (y)∣≤K∣x−y∣^a

$$\left.\mathrm{1}\left.\right)\left.\:\mathrm{Show}\:\mathrm{that}\:\:\mathrm{for}\:\mathrm{a}\in\right]\mathrm{01}\right]\mathrm{the}\:\mathrm{function}\:\:\mathrm{f}_{\mathrm{a}} \::\mathbb{R}_{+} \rightarrow\mathbb{R}\:\mathrm{defined}\:\mathrm{by}\:\mathrm{f}_{\mathrm{a}} \left(\mathrm{x}\right)=\mathrm{x}^{\mathrm{a}} \: \\ $$$$\mathrm{is}\:\:\:\mathrm{a}−\mathrm{holder}\:\mathrm{function}\:\:\mathrm{in}\:\mathrm{other}\:\mathrm{way}\:\:\mathrm{there}\:\mathrm{exist}\:\:\mathrm{K}>\mathrm{0}\:\mathrm{such}\:\mathrm{as}\:\forall\:\mathrm{x},\mathrm{y}>\mathrm{0}\: \\ $$$$\mid\mathrm{f}_{\mathrm{a}} \left(\mathrm{x}\right)−\mathrm{f}_{\mathrm{a}} \left(\mathrm{y}\right)\mid\leqslant\mathrm{K}\mid\mathrm{x}−\mathrm{y}\mid^{\mathrm{a}} \:\: \\ $$$$ \\ $$

Question Number 75040 Answers: 1 Comments: 0

Please can you help me to to show that: cos ((47Π)/(13))=sin ((23Π)/(26))=sin((3Π)/(26))

$$\mathrm{Please}\:\mathrm{can}\:\mathrm{you}\:\mathrm{help}\:\mathrm{me}\:\mathrm{to}\: \\ $$$$\mathrm{to}\:\mathrm{show}\:\mathrm{that}: \\ $$$$\mathrm{cos}\:\frac{\mathrm{47}\Pi}{\mathrm{13}}=\mathrm{sin}\:\frac{\mathrm{23}\Pi}{\mathrm{26}}=\mathrm{sin}\frac{\mathrm{3}\Pi}{\mathrm{26}} \\ $$

Question Number 75034 Answers: 3 Comments: 0

Question Number 75033 Answers: 1 Comments: 0

(4/(11)) < (x/y) < (3/8) x, y ∈ Z^+ min {x+y} = ?

$$\frac{\mathrm{4}}{\mathrm{11}}\:<\:\frac{{x}}{{y}}\:<\:\frac{\mathrm{3}}{\mathrm{8}} \\ $$$${x},\:{y}\:\:\in\:\:\mathbb{Z}^{+} \\ $$$${min}\:\left\{{x}+{y}\right\}\:\:=\:\:? \\ $$

Question Number 75027 Answers: 1 Comments: 1

Question Number 75013 Answers: 1 Comments: 0

The largest interval for which x^(12) −x^9 +x^4 −x+1>0 is (a)−4<x≤0 (b)0<x<1 (c)−100<x<100 (d)−∞<x<∞

$${The}\:{largest}\:{interval}\:{for}\:{which} \\ $$$${x}^{\mathrm{12}} −{x}^{\mathrm{9}} +{x}^{\mathrm{4}} −{x}+\mathrm{1}>\mathrm{0}\:{is} \\ $$$$\left({a}\right)−\mathrm{4}<{x}\leqslant\mathrm{0} \\ $$$$\left({b}\right)\mathrm{0}<{x}<\mathrm{1} \\ $$$$\left({c}\right)−\mathrm{100}<{x}<\mathrm{100} \\ $$$$\left({d}\right)−\infty<{x}<\infty \\ $$

Question Number 75001 Answers: 0 Comments: 2

A block of mass 0.2kg rests on an incline plane of 30° to the horizontal with a velocity of 12m/s.If the coefficient of sliding friction is 0.16, (i)determine how far up the plane the mass travels before stoping. (ii)if the block returns,what is the velocity of the block at the bottom of the plane. (g=9.8m/s)

$${A}\:{block}\:{of}\:{mass}\:\mathrm{0}.\mathrm{2}{kg}\:{rests}\:{on}\:{an}\:{incline} \\ $$$${plane}\:{of}\:\mathrm{30}°\:{to}\:{the}\:{horizontal}\:{with}\:{a} \\ $$$${velocity}\:{of}\:\mathrm{12}{m}/{s}.{If}\:{the}\:{coefficient}\:{of} \\ $$$${sliding}\:{friction}\:{is}\:\mathrm{0}.\mathrm{16}, \\ $$$$\left({i}\right){determine}\:{how}\:{far}\:{up}\:{the}\:{plane}\:{the} \\ $$$${mass}\:{travels}\:{before}\:{stoping}. \\ $$$$\left({ii}\right){if}\:{the}\:{block}\:{returns},{what}\:{is}\:{the} \\ $$$${velocity}\:{of}\:{the}\:{block}\:{at}\:{the}\:{bottom}\:{of}\:{the} \\ $$$${plane}. \\ $$$$ \\ $$$$\left({g}=\mathrm{9}.\mathrm{8}{m}/{s}\right) \\ $$

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