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Question Number 41302 Answers: 1 Comments: 1

calculate ∫_1 ^(+∞) (dx/(x^2 (√(x^2 +x+1))))

$${calculate}\:\:\int_{\mathrm{1}} ^{+\infty} \:\:\frac{{dx}}{{x}^{\mathrm{2}} \sqrt{{x}^{\mathrm{2}} +{x}+\mathrm{1}}} \\ $$

Question Number 41301 Answers: 1 Comments: 4

let f(x)=∫_0 ^∞ e^(−ax) ln(1+e^(−bx) )dx with a>0 and b>0 1) calculate (∂f/∂a)(x) 2) calculate (∂f/∂b)(x) 3)find the value of ∫_0 ^∞ e^(−2x) ln(1+e^(−x) )dx and ∫_0 ^∞ e^(−x) ln(1+e^(−2x) )dx .

$${let}\:{f}\left({x}\right)=\int_{\mathrm{0}} ^{\infty} \:\:{e}^{−{ax}} {ln}\left(\mathrm{1}+{e}^{−{bx}} \right){dx}\:{with}\:{a}>\mathrm{0}\:{and} \\ $$$${b}>\mathrm{0} \\ $$$$\left.\mathrm{1}\right)\:{calculate}\:\frac{\partial{f}}{\partial{a}}\left({x}\right) \\ $$$$\left.\mathrm{2}\right)\:{calculate}\:\frac{\partial{f}}{\partial{b}}\left({x}\right) \\ $$$$\left.\mathrm{3}\right){find}\:{the}\:{value}\:{of}\:\int_{\mathrm{0}} ^{\infty} \:{e}^{−\mathrm{2}{x}} {ln}\left(\mathrm{1}+{e}^{−{x}} \right){dx}\:{and} \\ $$$$\int_{\mathrm{0}} ^{\infty} \:\:{e}^{−{x}} {ln}\left(\mathrm{1}+{e}^{−\mathrm{2}{x}} \right){dx}\:. \\ $$

Question Number 41292 Answers: 1 Comments: 0

Question Number 41291 Answers: 2 Comments: 0

Let ABCD be a parallelogram whose diagonals intersect at P and ley O be the origin, then OA^(→) +OB^(→) +OC^(→) +OD^(→) equals

$$\mathrm{Let}\:{ABCD}\:\mathrm{be}\:\mathrm{a}\:\mathrm{parallelogram}\:\mathrm{whose} \\ $$$$\mathrm{diagonals}\:\mathrm{intersect}\:\mathrm{at}\:{P}\:\mathrm{and}\:\mathrm{ley}\:{O}\:\mathrm{be} \\ $$$$\mathrm{the}\:\mathrm{origin},\:\mathrm{then}\:\overset{\rightarrow} {{OA}}+\overset{\rightarrow} {{OB}}+\overset{\rightarrow} {{OC}}+\overset{\rightarrow} {{OD}}\: \\ $$$$\mathrm{equals} \\ $$

Question Number 41290 Answers: 1 Comments: 0

An electric pole PN is such that PN=12cm where N is the top of the pole and P the base .At a given moment of the day the shadow of the pole PN′ = PN. find a) the length NN′ b) the bearing of P from N.

$${An}\:{electric}\:{pole}\:{PN}\:{is}\:{such}\:{that}\:{PN}=\mathrm{12}{cm}\:{where}\:{N}\:{is}\:{the}\:{top}\:{of}\:{the}\:{pole}\:{and}\:{P}\:{the}\:{base} \\ $$$$.{At}\:{a}\:{given}\:{moment}\:{of}\:{the}\:{day}\:{the}\:\boldsymbol{{shadow}}\:\boldsymbol{{of}}\:\boldsymbol{{the}}\:\boldsymbol{{pole}}\:{PN}'\:=\:{PN}.\:{find}\: \\ $$$$\left.{a}\right)\:{the}\:{length}\:{NN}' \\ $$$$\left.{b}\right)\:{the}\:{bearing}\:{of}\:{P}\:{from}\:{N}. \\ $$

Question Number 41288 Answers: 1 Comments: 0

by using the knowledge of sequence and series show that the compound interest is given by An=P(1+((RT)/(100)))^n

Question Number 41280 Answers: 1 Comments: 1

find f(x) = ∫_0 ^1 arctan(xt^2 )dt

$${find}\:\:{f}\left({x}\right)\:=\:\int_{\mathrm{0}} ^{\mathrm{1}} \:\:{arctan}\left({xt}^{\mathrm{2}} \right){dt} \\ $$

Question Number 41279 Answers: 0 Comments: 1

let f(x)=∫_0 ^∞ arctan(xt^2 )dt . find a explicite form of f^′ (x)

$${let}\:{f}\left({x}\right)=\int_{\mathrm{0}} ^{\infty} \:\:\:{arctan}\left({xt}^{\mathrm{2}} \right){dt}\:. \\ $$$${find}\:\:{a}\:{explicite}\:{form}\:{of}\:{f}^{'} \left({x}\right) \\ $$

Question Number 41273 Answers: 0 Comments: 2

find f(x)=∫_0 ^(+∞) arctan(xt^2 )dt with x fromR .

$${find}\:\:{f}\left({x}\right)=\int_{\mathrm{0}} ^{+\infty} \:{arctan}\left({xt}^{\mathrm{2}} \right){dt}\:\:{with}\:{x}\:{fromR}\:. \\ $$