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AllQuestion and Answers: Page 1657

Question Number 33783 Answers: 1 Comments: 0

Two commodities X and Y cost $70.00 and $80.00 per kg respectively. If 34.5 kg of X is mixed with 26kg of Y and the mixture is sold at $85.00 per kg, calculate the percentage profit.

$$\mathrm{Two}\:\mathrm{commodities}\:\mathrm{X}\:\mathrm{and}\:\mathrm{Y}\:\mathrm{cost}\:\$\mathrm{70}.\mathrm{00}\:\mathrm{and}\:\$\mathrm{80}.\mathrm{00} \\ $$$$\mathrm{per}\:\mathrm{kg}\:\mathrm{respectively}.\:\mathrm{If}\:\mathrm{34}.\mathrm{5}\:\mathrm{kg}\:\mathrm{of}\:\mathrm{X}\:\mathrm{is}\:\mathrm{mixed}\:\mathrm{with}\: \\ $$$$\mathrm{26kg}\:\mathrm{of}\:\mathrm{Y}\:\mathrm{and}\:\mathrm{the}\:\mathrm{mixture}\:\mathrm{is}\:\mathrm{sold}\:\mathrm{at}\:\$\mathrm{85}.\mathrm{00}\:\mathrm{per}\:\mathrm{kg}, \\ $$$$\mathrm{calculate}\:\mathrm{the}\:\mathrm{percentage}\:\mathrm{profit}. \\ $$

Question Number 33824 Answers: 1 Comments: 0

two sphere with 10 cm radious and 1 kg mass and distence between this two is 1 m .after what time they will touch each other?

$$\mathrm{two}\:\mathrm{sphere}\:\mathrm{with}\:\mathrm{10}\:\mathrm{cm}\:\mathrm{radious}\:\mathrm{and} \\ $$$$\mathrm{1}\:\mathrm{kg}\:\mathrm{mass}\:\mathrm{and}\:\mathrm{distence}\:\mathrm{between} \\ $$$$\mathrm{this}\:\mathrm{two}\:\mathrm{is}\:\mathrm{1}\:\mathrm{m}\:.\mathrm{after}\:\mathrm{what}\:\mathrm{time}\:\mathrm{they} \\ $$$$\mathrm{will}\:\mathrm{touch}\:\mathrm{each}\:\mathrm{other}? \\ $$

Question Number 33767 Answers: 1 Comments: 0

Question Number 33766 Answers: 1 Comments: 0

a−(1/a)=4 (√(a^2 +(1/a^2 )))−(√((a+(1/a))^2 ))−(√((a−2)^2 ))=(√x)−(√y) what is [x+y]?

$${a}−\frac{\mathrm{1}}{{a}}=\mathrm{4} \\ $$$$\sqrt{{a}^{\mathrm{2}} +\frac{\mathrm{1}}{{a}^{\mathrm{2}} }}−\sqrt{\left({a}+\frac{\mathrm{1}}{{a}}\right)^{\mathrm{2}} }−\sqrt{\left({a}−\mathrm{2}\right)^{\mathrm{2}} }=\sqrt{{x}}−\sqrt{{y}} \\ $$$${what}\:{is}\:\left[{x}+{y}\right]? \\ $$

Question Number 33764 Answers: 1 Comments: 0

2x−y=(1/((√5)−2)) x+2y=(1/((√5)+2)) [3x^2 −8xy−3y^2 ]?

$$\mathrm{2}{x}−{y}=\frac{\mathrm{1}}{\sqrt{\mathrm{5}}−\mathrm{2}} \\ $$$${x}+\mathrm{2}{y}=\frac{\mathrm{1}}{\sqrt{\mathrm{5}}+\mathrm{2}} \\ $$$$\left[\mathrm{3}{x}^{\mathrm{2}} −\mathrm{8}{xy}−\mathrm{3}{y}^{\mathrm{2}} \right]? \\ $$

Question Number 33759 Answers: 0 Comments: 9

solve : ∫_(−π/2) ^(π/2) ((sin θ )/(√( R^2 + r^2 − 2rR cos θ))) dθ

$${solve}\::\: \\ $$$$\:\underset{−\pi/\mathrm{2}} {\overset{\pi/\mathrm{2}} {\int}}\:\:\frac{{sin}\:\theta\:}{\sqrt{\:{R}^{\mathrm{2}} \:+\:{r}^{\mathrm{2}} \:−\:\mathrm{2}{rR}\:{cos}\:\theta}}\:{d}\theta \\ $$

Question Number 33756 Answers: 1 Comments: 0

Prove that if circum-circle and in-circle of a triangle are concentric, the triangle is an equalateral triangle.

$$\mathrm{Prove}\:\mathrm{that}\:\mathrm{if}\:\boldsymbol{\mathrm{circum}}-\boldsymbol{\mathrm{circle}}\:\mathrm{and} \\ $$$$\boldsymbol{\mathrm{in}}-\boldsymbol{\mathrm{circle}}\:\mathrm{of}\:\mathrm{a}\:\mathrm{triangle}\:\mathrm{are}\:\boldsymbol{\mathrm{concentric}}, \\ $$$$\mathrm{the}\:\mathrm{triangle}\:\mathrm{is}\:\mathrm{an}\:\boldsymbol{\mathrm{equalateral}}\:\boldsymbol{\mathrm{triangle}}. \\ $$

Question Number 33789 Answers: 3 Comments: 0

If the equation 2x^2 +14x−15=0 is divided by (x−4), the remainder is

$$\mathrm{If}\:\mathrm{the}\:\mathrm{equation}\:\:\mathrm{2}{x}^{\mathrm{2}} +\mathrm{14}{x}−\mathrm{15}=\mathrm{0}\:\mathrm{is} \\ $$$$\mathrm{divided}\:\mathrm{by}\:\left({x}−\mathrm{4}\right),\:\mathrm{the}\:\mathrm{remainder}\:\mathrm{is} \\ $$

Question Number 34652 Answers: 2 Comments: 2

a point charge q is placed at (0,a/2,0) . find flux due to point charge through a square sheet of side a in xz plane whose centre coincides with orign. ( do not use gauss law)

$${a}\:{point}\:{charge}\:{q}\:{is}\:{placed} \\ $$$${at}\:\left(\mathrm{0},{a}/\mathrm{2},\mathrm{0}\right)\:.\:{find}\:{flux} \\ $$$${due}\:{to}\:{point}\:{charge}\:{through} \\ $$$${a}\:{square}\:{sheet}\:{of}\:{side}\:{a}\:\: \\ $$$${in}\:{xz}\:{plane}\:{whose}\:{centre} \\ $$$${coincides}\:{with}\:{orign}. \\ $$$$\left(\:{do}\:{not}\:{use}\:{gauss}\:{law}\right) \\ $$

Question Number 33753 Answers: 1 Comments: 0

Question Number 33747 Answers: 0 Comments: 0

Calculate ∫_(−∞) ^(+∞) e^(−x^2 ) dx using Residue theorem

$${Calculate}\:\int_{−\infty} ^{+\infty} {e}^{−{x}^{\mathrm{2}} } {dx}\:\:{using}\:\:{Residue}\:{theorem} \\ $$

Question Number 33743 Answers: 0 Comments: 1

let p(x)=(1+x^2 )(1+x^4 )....(1+x^2^n ) with n integr 1) find the roots of p(x) 2) factorize p(x) inside C[x]

$${let}\:{p}\left({x}\right)=\left(\mathrm{1}+{x}^{\mathrm{2}} \right)\left(\mathrm{1}+{x}^{\mathrm{4}} \right)....\left(\mathrm{1}+{x}^{\mathrm{2}^{{n}} } \right)\:{with}\:{n}\:{integr} \\ $$$$\left.\mathrm{1}\right)\:{find}\:{the}\:{roots}\:{of}\:{p}\left({x}\right) \\ $$$$\left.\mathrm{2}\right)\:{factorize}\:{p}\left({x}\right)\:{inside}\:{C}\left[{x}\right] \\ $$

Question Number 33744 Answers: 0 Comments: 1

let P_n (x)=(1+x^2 )(1+x^4 )....(1+x^2^n ) calculate lim_(n→+∞) ∫_0 ^x P_n (t)dt with 0<x<1 .

$${let}\:\:{P}_{{n}} \left({x}\right)=\left(\mathrm{1}+{x}^{\mathrm{2}} \right)\left(\mathrm{1}+{x}^{\mathrm{4}} \right)....\left(\mathrm{1}+{x}^{\mathrm{2}^{{n}} } \right) \\ $$$${calculate}\:\:{lim}_{{n}\rightarrow+\infty} \int_{\mathrm{0}} ^{{x}} \:{P}_{{n}} \left({t}\right){dt}\:\:{with}\:\:\mathrm{0}<{x}<\mathrm{1}\:. \\ $$

Question Number 33737 Answers: 1 Comments: 3

find the value of ∫_0 ^∞ ((cos(xt))/((t^2 + x^2 )^2 )) dt .

$${find}\:{the}\:{value}\:{of}\:\:\int_{\mathrm{0}} ^{\infty} \:\:\:\:\frac{{cos}\left({xt}\right)}{\left({t}^{\mathrm{2}} \:+\:{x}^{\mathrm{2}} \right)^{\mathrm{2}} }\:{dt}\:. \\ $$

Question Number 33736 Answers: 2 Comments: 1

find the value of ∫_(−∞) ^(+∞) (x^2 /((1+x +x^2 )^2 ))dx

$${find}\:{the}\:{value}\:{of}\:\:\int_{−\infty} ^{+\infty} \:\:\:\:\:\frac{{x}^{\mathrm{2}} }{\left(\mathrm{1}+{x}\:+{x}^{\mathrm{2}} \right)^{\mathrm{2}} }{dx} \\ $$

Question Number 33735 Answers: 0 Comments: 1

calculate ∫_0 ^∞ ((cos(2x)dx)/((x^2 +1)( 2x^2 +3))) .

$${calculate}\:\:\int_{\mathrm{0}} ^{\infty} \:\:\:\:\:\:\frac{{cos}\left(\mathrm{2}{x}\right){dx}}{\left({x}^{\mathrm{2}} +\mathrm{1}\right)\left(\:\mathrm{2}{x}^{\mathrm{2}} \:+\mathrm{3}\right)}\:. \\ $$

Question Number 33733 Answers: 1 Comments: 2

Solve : (x−2) × [x] = {x} −1 . • [.]= greatest integer function • {.}= fractional part function.

$${Solve}\:: \\ $$$$\left({x}−\mathrm{2}\right)\:×\:\left[{x}\right]\:=\:\left\{{x}\right\}\:−\mathrm{1}\:. \\ $$$$\bullet\:\left[.\right]=\:{greatest}\:{integer}\:{function} \\ $$$$\bullet\:\left\{.\right\}=\:{fractional}\:{part}\:\:{function}. \\ $$

Question Number 33724 Answers: 2 Comments: 1

if three persons selected at random are stopped on a street,what is the probability that (i)all were born on a friday? (ii)two were born on a friday and the others on a thursday? (iii)none was born on a friday

Question Number 33719 Answers: 1 Comments: 1

simplify S_n (x) =(1+x^2 )(1+x^4 )....(1+x^2^n ) 2) find lim_(n→+∞) S_n (x) if ∣x∣<1 .

$${simplify}\:{S}_{{n}} \left({x}\right)\:=\left(\mathrm{1}+{x}^{\mathrm{2}} \right)\left(\mathrm{1}+{x}^{\mathrm{4}} \right)....\left(\mathrm{1}+{x}^{\mathrm{2}^{{n}} } \right) \\ $$$$\left.\mathrm{2}\right)\:{find}\:{lim}_{{n}\rightarrow+\infty} \:{S}_{{n}} \left({x}\right)\:{if}\:\mid{x}\mid<\mathrm{1}\:. \\ $$

Question Number 33718 Answers: 0 Comments: 2

find Σ_(n=1) ^(+∞) arctan( ((ln(1+(1/(n+1))) −ln(1+(1/n)))/(1+(1 +(1/n))(1+(1/(n+1))))))

$${find}\:\:\sum_{{n}=\mathrm{1}} ^{+\infty} {arctan}\left(\:\frac{{ln}\left(\mathrm{1}+\frac{\mathrm{1}}{{n}+\mathrm{1}}\right)\:−{ln}\left(\mathrm{1}+\frac{\mathrm{1}}{{n}}\right)}{\mathrm{1}+\left(\mathrm{1}\:+\frac{\mathrm{1}}{{n}}\right)\left(\mathrm{1}+\frac{\mathrm{1}}{\left.{n}+\mathrm{1}\right)}\right.}\right) \\ $$

Question Number 33716 Answers: 1 Comments: 1

calculate Σ_(n=0) ^∞ arctan( ((e^(n+1) −e^n )/(1+e^(2n+1) ))) .

$${calculate}\:\:\sum_{{n}=\mathrm{0}} ^{\infty} \:\:\:{arctan}\left(\:\frac{{e}^{{n}+\mathrm{1}} \:\:−{e}^{{n}} }{\mathrm{1}+{e}^{\mathrm{2}{n}+\mathrm{1}} }\right)\:. \\ $$

Question Number 33717 Answers: 1 Comments: 2

find the value of Σ_(n=0) ^∞ artan( (((√(n+1)) −(√n))/(1+(√(n^2 +n)))) )

$${find}\:{the}\:{value}\:{of}\:\:\sum_{{n}=\mathrm{0}} ^{\infty} \:{artan}\left(\:\frac{\sqrt{{n}+\mathrm{1}}\:−\sqrt{{n}}}{\mathrm{1}+\sqrt{{n}^{\mathrm{2}} +{n}}}\:\right) \\ $$

Question Number 33713 Answers: 1 Comments: 4

find tbe value of Σ_(n=2) ^∞ ((n^2 −n+1)/((n−1)^2 (n+1)^2 )) .

$${find}\:{tbe}\:{value}\:{of}\:\sum_{{n}=\mathrm{2}} ^{\infty} \:\frac{{n}^{\mathrm{2}} −{n}+\mathrm{1}}{\left({n}−\mathrm{1}\right)^{\mathrm{2}} \left({n}+\mathrm{1}\right)^{\mathrm{2}} }\:. \\ $$

Question Number 33710 Answers: 0 Comments: 1

1) find the radius of convergence?for Σ_(n=1) ^∞ (x^n /(n(n+1)(n+2))) and calculate its sum 2) find the value of Σ_(n=1) ^∞ (((−1)^n )/(n 2^n (n+1)(n+2)))

$$\left.\mathrm{1}\right)\:{find}\:{the}\:{radius}\:{of}\:{convergence}?{for} \\ $$$$\sum_{{n}=\mathrm{1}} ^{\infty} \:\:\:\frac{{x}^{{n}} }{{n}\left({n}+\mathrm{1}\right)\left({n}+\mathrm{2}\right)}\:{and}\:{calculate}\:{its}\:{sum} \\ $$$$ \\ $$$$\left.\mathrm{2}\right)\:{find}\:{the}\:{value}\:{of}\:\sum_{{n}=\mathrm{1}} ^{\infty} \:\:\:\frac{\left(−\mathrm{1}\right)^{{n}} }{{n}\:\mathrm{2}^{{n}} \left({n}+\mathrm{1}\right)\left({n}+\mathrm{2}\right)} \\ $$

Question Number 33709 Answers: 0 Comments: 1

find Σ_(n=0) ^∞ (n+1)x^(3n) 2) calculate Σ_(n=0) ^∞ ((n+1)/8^n ) .

$${find}\:\:\sum_{{n}=\mathrm{0}} ^{\infty} \:\left({n}+\mathrm{1}\right){x}^{\mathrm{3}{n}} \\ $$$$\left.\mathrm{2}\right)\:{calculate}\:\:\sum_{{n}=\mathrm{0}} ^{\infty} \:\:\:\frac{{n}+\mathrm{1}}{\mathrm{8}^{{n}} }\:. \\ $$

Question Number 33708 Answers: 0 Comments: 0

find Σ_(n=0) ^∞ (n+1)x^(3n) 2) calculate Σ_(n=0) ^∞ ((n+1)/8^n ) .

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