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Mariusz M

Rejestracja: 11 Sep 2010
Online Ostatnio: dziś, 00:16
*****

#130280 Całka z demotów

Napisane przez Mariusz M w 27.09.2018 - 13:01

Ostrogradskim też można

 

\gcd{Q\left(x\right),Q'\left(x\right)}

 

możesz liczyć na dwa sposoby

 

1. Korzystając z rozkładu na czynniki

2. Korzystając z algorytmu kolejnych dzieleń
Bierzesz reszty z kolejnych dzieleń
Przypomina to algorytm Euklidesa dla liczb

 

\frac{1}{32}\int{\frac{2160t^3-9086t^2+12728t-5937}{\left(2t-3\right)^4}\mbox{d}t}=\frac{a_{2}t^2+a_{1}t+a_{0}}{\left(2t-3\right)^3}+\int{\frac{b_{0}}{2t-3}\mbox{d}t}\\</p>\\<p>\frac{1}{32}\cdot\frac{2160t^3-9086t^2+12728t-5937}{\left(2t-3\right)^4}=\frac{\left(2a_{2}t+a_{1}\right)\left(2t-3\right)^3-6\left(2t-3\right)^2\left(a_{2}t^2+a_{1}t+a_{0}\right)}{\left(2t-3\right)^6}+\frac{b_{0}}{2t-3}\\</p>\\<p>\frac{1}{32}\cdot\frac{2160t^3-9086t^2+12728t-5937}{\left(2t-3\right)^4}=\frac{\left(2a_{2}t+a_{1}\right)\left(2t-3\right)-6\left(a_{2}t^2+a_{1}t+a_{0}\right)}{\left(2t-3\right)^4}+\frac{b_{0}\left(2t-3\right)^3}{\left(2t-3\right)^4}\\</p>\\<p>\frac{1}{32}\cdot\left(2160t^3-9086t^2+12728t-5937\right)=\left(2a_{2}t+a_{1}\right)\left(2t-3\right)-6\left(a_{2}t^2+a_{1}t+a_{0}\right)+b_{0}\left(2t-3\right)^3\\</p>\\<p>\frac{1}{32}\cdot\left(2160t^3-9086t^2+12728t-5937\right)=\left(4a_{2}t^2-6a_{2}t+2a_{1}t-3a_{1}\right)-\left(6a_{2}t^2+6a_{1}t+6a_{0}\right)+b_{0}\left(8t^3-36t^2+54t-27\right)\\</p>\\<p>\frac{1}{32}\cdot\left(2160t^3-9086t^2+12728t-5937\right)=8b_{0}t^3+\left(-36b_{0}-2a_{2}\right)t^2+\left(54b_{0}-6a_{2}-4a_{1}\right)t+\left(-27b_{0}-3a_{1}-6a_{0}\right)\\</p>\\<p>


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#130257 UPROŚĆ 4 Algebra Boola

Napisane przez Mariusz M w 17.09.2018 - 19:49

y=a\overline{c}+a\overline{b}+b\overline{c}+b\left(\overline{a}+\overline{c}\right)+\left(\overline{a}+\overline{c}\right)\\</p>\\<p>y=a\overline{c}+a\overline{b}+b\overline{c}+\left(b+1\right)\left(\overline{a}+\overline{c}\right)\\</p>\\<p>y=a\overline{c}+a\overline{b}+b\overline{c}+\overline{a}+\overline{c}\\</p>\\<p>y=a\overline{c}+a\overline{b}+b\overline{c}+\overline{a}+\overline{c}+a\overline{a}\\</p>\\<p>y=a\left(\overline{c}+\overline{a}\right)+\left(\overline{c}+\overline{a}\right)+a\overline{b}+b\overline{c}\\</p>\\<p>y=(1+a)\left(\overline{c}+\overline{a}\right)+a\overline{b}+b\overline{c}\\</p>\\<p>y=\left(\overline{c}+\overline{a}\right)+a\overline{b}+b\overline{c}\\</p>\\<p>y=\overline{c}+\overline{a}+a\overline{b}+b\overline{c}\\</p>\\<p>y=\overline{c}\left(1+b\right)+\overline{a}+a\overline{b}\\</p>\\<p>y=\overline{c}+\overline{a}+a\overline{b}\\</p>\\<p>y=\overline{c}+\overline{a}\left(1+\overline{b}\right)+a\overline{b}\\</p>\\<p>y=\overline{c}+\overline{a}+\overline{a}\overline{b}+a\overline{b}\\</p>\\<p>y=\overline{c}+\overline{a}+\overline{b}\left(a+\overline{a}\right)\\</p>\\<p>y=\overline{c}+\overline{a}+\overline{b}\\<br>\\

 

Jeżeli nic nie zgubiłem podczas obliczeń to wynik powinien być dobry
Nawet jeśli pomyliłem się w obliczeniach to sposób jest dobry

 


  • 1


#130256 Całka z demotów

Napisane przez Mariusz M w 17.09.2018 - 11:39

Nie lepiej było zastosować pierwsze podstawienie Eulera
\sqrt{x^2-3x+2}=t-x

 

Po zastosowaniu liniowości mielibyśmy całkę z potęgi

Ale tak jest modnie po amerykańsku

 

 

\int{\frac{3x^3-x^2+2x-4}{\sqrt{x^2-3x+2}}\mbox{d}x}\\</p>\\<p>\sqrt{x^2-3x+2}=t-x\\</p>\\<p>x^2-3x+2=t^2-2tx+x^2\\<br>\\-3x+2=t^2-2tx\\</p>\\<p>t^2-2=2tx-3x\\</p>\\<p>x\left(2t-3\right)=t^2-2\\</p>\\<p>x = \frac{t^2-2}{2t-3}\\</p>\\<p>t-x=\frac{t^2-3t+2}{2t-3}\\</p>\\<p>\mbox{d}x=\frac{2t\left(2t-3\right)-2(t^2-2)}{(2t-3)^2}\mbox{d}t\\</p>\\<p>\mbox{d}x=\frac{2t^2-6t+4}{(2t-3)^2}\mbox{d}t\\</p>\\<p>3x^3-x^2+2x-4=\frac{3\left(t^2-2\right)^3-(t^2-2)^2(2t-3)+2(t^2-2)(2t-3)^2-4(2t-3)^3}{\left(2t-3\right)^2}\\</p>\\<p>3t^6-18t^4+36t^2-24\\<br>\\-(2t^5-3t^4-8t^3+12t^2+8t-12)\\<br>\\8t^4-24t^3+2t^2+48t-36\\<br>\\-(32t^3-144t^2+216t-108)\\<br>\\3t^6-2t^5-7t^4-48t^3+170t^2-176t+60\\</p>\\<p>3x^3-x^2+2x-4=\frac{3t^6-2t^5-7t^4-48t^3+170t^2-176t+60}{(2t-3)^3}\\</p>\\<p>\int{\frac{3t^6-2t^5-7t^4-48t^3+170t^2-176t+60}{(2t-3)^3}\cdot\frac{2t-3}{t^2-3t+2}\cdot\frac{2\left(t^2-3t+2\right)}{\left(2t-3\right)^2}\mbox{d}t}\\</p>\\<p>2\int{\frac{3t^6-2t^5-7t^4-48t^3+170t^2-176t+60}{\left(2t-3\right)^4}\mbox{d}t}<br>\\\begin{tabular}{c|c|c|c|c|c|c|c|}</p>\\<p>& 3&-2&-7&-48&170&-176&60\\ \hline</p>\\<p>\frac{3}{2}&3&\frac{5}{2}&-\frac{13}{4}&-\frac{423}{8}&\frac{1451}{16}&-\frac{1279}{32}&\frac{3}{64}\\ \hline</p>\\<p>\frac{3}{2}&3&7&\frac{29}{4}&-42&\frac{443}{16}&\frac{25}{16}& \\ \hline<br>\\\frac{3}{2}&3&\frac{23}{2}&\frac{49}{2}&-\frac{21}{4}&\frac{317}{16}&& \\ \hline</p>\\<p>\frac{3}{2}&3&16&\frac{97}{2}&\frac{135}{2}&&& \\ \hline<br>\\\frac{3}{2}&3&\frac{41}{2}&\frac{317}{4}&&&& \\ \hline</p>\\<p>\frac{3}{2}&3&25&&&&& \\ \hline<br>\\\frac{3}{2}&3&&&&&& \\ \hline</p>\\<p>\end{tabular}\\</p>\\<p>3t^6-2t^5-7t^4-48t^3+170t^2-176t+60=3\left(t-\frac{3}{2}\right)^6+25\left(t-\frac{3}{2}\right)^5+\frac{317}{4}\left(t-\frac{3}{2}\right)^4+\frac{135}{2}\left(t-\frac{3}{2}\right)^3+\frac{317}{16}\left(t-\frac{3}{2}\right)^2+\frac{25}{16}\left(t-\frac{3}{2}\right)+\frac{3}{64}\\<br>\\3t^6-2t^5-7t^4-48t^3+170t^2-176t+60=\frac{3}{64}\left(2t-3\right)^6+\frac{25}{32}\left(2t-3\right)^5+\frac{317}{64}\left(2t-3\right)^4+\frac{135}{16}\left(2t-3\right)^3+\frac{317}{64}\left(2t-3\right)^2+\frac{25}{32}\left(2t-3\right)+\frac{3}{64}\\</p>\\<p>\frac{3}{32}\int{\left(2t-3\right)^2\mbox{d}t}+\frac{25}{16}\int{\left(2t-3\right)\mbox{d}t}+\frac{317}{32}\int{\mbox{d}t}+\frac{317}{32}\int{\frac{\mbox{d}t}{\left(2t-3\right)^2}}+\frac{25}{16}\int{\frac{\mbox{d}t}{\left(2t-3\right)^3}\mbox{d}t}+\frac{3}{32}\int{\frac{\mbox{d}t}{\left(2t-3\right)^4}}+\frac{135}{8}\int{\frac{\mbox{d}t}{\left(2t-3\right)}}</p>\\<p>

 

Po scałkowaniu dostaniemy liczbę

=-\frac{1}{8}\left(101\sqrt{2}+135\ln{\left(\sqrt{2}-1\right)}\right)


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#130210 Oblicz całkę

Napisane przez Mariusz M w 16.07.2018 - 09:10

Jakiś czas temu na innym forum widziałem całkę 

 

\int{\frac{x}{\sqrt{e^{x}+\left(x+2\right)^2}}\mbox{d}x}

 

 

Wiem jak ją obliczyć ale jestem ciekawy czy wam sprawi kłopot jej policzenie 

Dodatkowo dodam że Wolfram ma kłopoty z jej policzeniem a także pewni użytkownicy 

forum twierdzili że nie da się jej elementarnie policzyć 

 


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#129813 cAŁAK 7

Napisane przez Mariusz M w 26.11.2017 - 03:43

Metoda Ostrogradskiego też będzie wymagała ośmiu współczynników , (po zastosowaniu wystarczy pobawić się licznikiem aby uzyskać dalszy rozkład)

Tutaj można pobawić się częściami aby uprościć sobie całkę

 

8(4x^2-2x-3)=(8x-2)(4x-1)-26\\</p>\\<p>(8x-2)(4x-1)-8(4x^2-2x-3)=26\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^4}\mbox{d}x}=\frac{1}{26}\int{\frac{(8x-2)(4x-1)-8(4x^2-2x-3)}{(4x^2-2x-3)^4}\mbox{d}x}\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^4}\mbox{d}x}=\frac{1}{26}\left(\int{\frac{(8x-2)(4x-1)}{(4x^2-2x-3)^4}}-8\int{\frac{(4x^2-2x-3)}{(4x^2-2x-3)^4}\mbox{d}x}\right)\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^4}\mbox{d}x}=\frac{1}{26}\left(\int{(4x-1)\frac{(8x-2)}{(4x^2-2x-3)^4}\mbox{d}x}-8\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}\right)\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^4}\mbox{d}x}=\frac{1}{26}\left(-\frac{1}{3}\frac{4x-1}{(4x^2-2x-3)^3}+\frac{4}{3}\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}-8\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}\right)\\</p>\\<p></p>\\<p>\int{\frac{1}{(4x^2-2x-3)^4}\mbox{d}x}=\frac{1}{26}\left(-\frac{1}{3}\frac{4x-1}{(4x^2-2x-3)^3}-\frac{20}{3}\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}\right)\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^4}\mbox{d}x}=-\frac{1}{78}\frac{4x-1}{(4x^2-2x-3)^3}-\frac{10}{39}\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}=\frac{1}{26}\int{\frac{(8x-2)(4x-1)-8(4x^2-2x-3)}{(4x^2-2x-3)^3}\mbox{d}x}\\</p>\\<p></p>\\<p>\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}=\frac{1}{26}\left(\int{\frac{(8x-2)(4x-1)}{(4x^2-2x-3)^3}}-8\int{\frac{(4x^2-2x-3)}{(4x^2-2x-3)^3}\mbox{d}x}\right)\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}=\frac{1}{26}\left(\int{(4x-1)\frac{(8x-2)}{(4x^2-2x-3)^3}\mbox{d}x}-8\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}\right)\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}=\frac{1}{26}\left(-\frac{1}{2}\frac{4x-1}{(4x^2-2x-3)^2}+2\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}-8\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}\right)\\</p>\\<p></p>\\<p>\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}=\frac{1}{26}\left(-\frac{1}{2}\frac{4x-1}{(4x^2-2x-3)^2}-6\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}\right)\\<br>\\\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}=-\frac{1}{52}\frac{4x-1}{(4x^2-2x-3)^2}-\frac{3}{13}\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}=\frac{1}{26}\int{\frac{(8x-2)(4x-1)-8(4x^2-2x-3)}{(4x^2-2x-3)^2}\mbox{d}x}\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}=\frac{1}{26}\left(\int{\frac{(8x-2)(4x-1)}{(4x^2-2x-3)^2}\mbox{d}x}-8\int{\frac{(4x^2-2x-3)}{(4x^2-2x-3)^2}\mbox{d}x}\right)\\</p>\\<p></p>\\<p>\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}=\frac{1}{26}\left((4x-1)\int{\frac{(8x-2)}{(4x^2-2x-3)^2}\mbox{d}x}-8\int{\frac{1}{4x^2-2x-3}\mbox{d}x}\right)\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}=\frac{1}{26}\left(-\frac{4x-1}{4x^2-2x-3}+4\int{\frac{1}{4x^2-2x-3}\mbox{d}x}-8\int{\frac{1}{4x^2-2x-3}\mbox{d}x}\right)\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}=\frac{1}{26}\left(-\frac{4x-1}{4x^2-2x-3}-4\int{\frac{1}{4x^2-2x-3}\mbox{d}x}\right)\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}=-\frac{1}{26}\frac{4x-1}{4x^2-2x-3}-\frac{\sqrt{13}}{169}\int{\frac{4(4x-1+\sqrt{13})-4(4x-1-\sqrt{13})}{16x^2-8x-12}\mbox{d}x}\\<br>\\\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}=-\frac{1}{26}\frac{4x-1}{4x^2-2x-3}-\frac{\sqrt{13}}{169}\left(\int{\frac{4}{(4x-1-\sqrt{13})}\mbox{d}x}-\int{\frac{4}{(4x-1+\sqrt{13})}}\right)\\<br>\\\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}=-\frac{1}{26}\frac{4x-1}{4x^2-2x-3}-\frac{\sqrt{13}}{169}\ln{\left|\frac{4x-1-\sqrt{13}}{4x-1+\sqrt{13}}\right|}\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}=-\frac{1}{52}\frac{4x-1}{(4x^2-2x-3)^2}-\frac{3}{13}\int{\frac{1}{(4x^2-2x-3)^2}\mbox{d}x}\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}=-\frac{1}{52}\frac{4x-1}{(4x^2-2x-3)^2}-\frac{3}{13}\left(-\frac{1}{26}\frac{4x-1}{4x^2-2x-3}-\frac{\sqrt{13}}{169}\ln{\left|\frac{4x-1-\sqrt{13}}{4x-1+\sqrt{13}}\right|}\right)\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}=-\frac{1}{52}\frac{4x-1}{(4x^2-2x-3)^2}+\frac{3}{338}\frac{4x-1}{4x^2-2x-3}+\frac{3\sqrt{13}}{2197}\ln{\left|\frac{4x-1-\sqrt{13}}{4x-1+\sqrt{13}}\right|}\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^4}\mbox{d}x}=-\frac{1}{78}\frac{4x-1}{(4x^2-2x-3)^3}-\frac{10}{39}\int{\frac{1}{(4x^2-2x-3)^3}\mbox{d}x}\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^4}\mbox{d}x}=-\frac{1}{78}\frac{4x-1}{(4x^2-2x-3)^3}-\frac{10}{39}\left(-\frac{1}{52}\frac{4x-1}{(4x^2-2x-3)^2}+\frac{3}{338}\frac{4x-1}{4x^2-2x-3}+\frac{3\sqrt{13}}{2197}\ln{\left|\frac{4x-1-\sqrt{13}}{4x-1+\sqrt{13}}\right|}\right)\\</p>\\<p>\int{\frac{1}{(4x^2-2x-3)^4}\mbox{d}x}=-\frac{1}{78}\frac{4x-1}{(4x^2-2x-3)^3}+\frac{5}{1014}\frac{4x-1}{(4x^2-2x-3)^2}-\frac{5}{2197}\frac{4x-1}{4x^2-2x-3}-\frac{10\sqrt{13}}{28561}\ln{\left|\frac{4x-1-\sqrt{13}}{4x-1+\sqrt{13}}\right|}+C\\<br>\\


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#129812 Całka 30

Napisane przez Mariusz M w 26.11.2017 - 01:15

\int{\frac{x}{\left(x^2+2x+2\right)^2}\mbox{d}x}=\frac{a_{1}x+a_{0}}{x^2+2x+2}+\int{\frac{b_{1}x+b_{0}}{x^2+2x+2}\mbox{d}x}\\</p>\\<p>\frac{x}{\left(x^2+2x+2\right)^2}=\frac{a_{1}(x^2+2x+2)-(a_{1}x+a_{0})(2x+2)}{(x^2+2x+2)^2}+\frac{b_{1}x+b_{0}}{x^2+2x+2}\\</p>\\<p>\frac{x}{\left(x^2+2x+2\right)^2}=\frac{a_{1}x^2+2a_{1}x+2a_{1}-(2a_{1}x^2+2a_{1}x+2a_{0}x+2a_{0})}{(x^2+2x+2)^2}+\frac{b_{1}x+b_{0}}{x^2+2x+2}\\</p>\\<p></p>\\<p>\frac{x}{\left(x^2+2x+2\right)^2}=\frac{a_{1}x^2+2a_{1}x+2a_{1}-(2a_{1}x^2+2a_{1}x+2a_{0}x+2a_{0})+(b_{1}x+b_{0})(x^2+2x+2)}{(x^2+2x+2)^2}\\</p>\\<p>x=a_{1}x^2+2a_{1}x+2a_{1}-(2a_{1}x^2+2a_{1}x+2a_{0}x+2a_{0})+(b_{1}x+b_{0})(x^2+2x+2)\\</p>\\<p>x=a_{1}x^2+2a_{1}x+2a_{1}-2a_{1}x^2-2a_{1}x-2a_{0}x-2a_{0}+b_{1}x^3+2b_{1}x^2+2b_{1}x+b_{0}x^2+2b_{0}x+2b_{0}\\</p>\\<p>x=b_{1}x^3+(2b_{1}+b_{0}-a_{1})x^2+(2b_{1}+2b_{0}-2a_{0})x+2b_{0}+2a_{1}-2a_{0}\\</p>\\<p>\begin{cases}b_{1}=0\\2b_{1}+b_{0}-a_{1}=0\\2b_{1}+2b_{0}-2a_{0}=1\\2b_{0}+2a_{1}-2a_{0}=0 \end{cases}\\<br>\\\begin{cases}b_{1}=0\\b_{0}=a_{1}\\2a_{1}-2a_{0}=1\\4a_{1}-2a_{0}=0 \end{cases}\\<br>\\\begin{cases}b_{1}=0\\b_{0}=a_{1}\\2a_{1}=-1\\a_{0}=2a_{1} \end{cases}\\<br>\\\begin{cases}b_{1}=0\\2b_{0}=-1\\2a_{1}=-1\\a_{0}=-1 \end{cases}\\<br>\\\int{\frac{x}{\left(x^2+2x+2\right)^2}\mbox{d}x}=-\frac{1}{2}\frac{x+2}{x^2+2x+2}-\frac{1}{2}\int{\frac{\mbox{d}x}{(x+1)^2+1}}\\</p>\\<p>\int{\frac{x}{\left(x^2+2x+2\right)^2}\mbox{d}x}=-\frac{1}{2}\frac{x+2}{x^2+2x+2}-\frac{1}{2}\arctan{(x+1)}+C\\<br>\\

Można jeszcze bawić się całkowaniem przez części

 


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#129608 Całka funkcji trygonometrycznej

Napisane przez Mariusz M w 18.09.2017 - 23:26

\int{\sqrt{\tan^{2}{\left(x\right)}+4}\mbox{d}x}\\</p>\\<p>\sqrt{\tan^{2}{\left(x\right)}+4}=t-\tan{\left(x\right)}\\</p>\\<p>\tan^{2}{\left(x\right)}+4=t^2-2t\tan{\left(x\right)}+\tan^{2}{\left(x\right)}\\</p>\\<p>4=t^2-2t\tan{\left(x\right)}\\</p>\\<p>2t\tan{\left(x\right)}=t^2-4\\</p>\\<p>\tan{\left(x\right)}=\frac{t^2-4}{2t}\\</p>\\<p>\left(1+\tan^2{\left(x\right)}\right)\mbox{d}x=\frac{2t\cdot 2t-2\left(t^2-4\right)}{4t^2}\mbox{d}t\\</p>\\<p>\left(1+\frac{t^4-8t^2+16}{4t^2}\right)\mbox{d}x=\frac{t^2+4}{2t^2}\mbox{d}t\\</p>\\<p>\frac{t^4-4t^2+16}{4t^2}\mbox{d}x=\frac{t^2+4}{2t^2}\mbox{d}t\\</p>\\<p>\mbox{d}x=\frac{t^2+4}{2t^2}\cdot\frac{4t^2}{t^4-4t^2+16}\mbox{d}t\\</p>\\<p>\mbox{d}x=2\frac{t^2+4}{t^4-4t^2+16}\mbox{d}t\\</p>\\<p>\sqrt{\tan^{2}{\left(x\right)}+4}=t-\frac{t^2-4}{2t}\\</p>\\<p>\sqrt{\tan^{2}{\left(x\right)}+4}=\frac{t^2+4}{2t}\\</p>\\<p>\int{\frac{\left(t^2+4\right)^2}{t\left(t^4-4t^2+16\right)}\mbox{d}t}\\</p>\\<p>\frac{1}{2}\int{\frac{2t\left(t^2+4\right)^2}{t^2\left(t^4-4t^2+16\right)}\mbox{d}t}\\</p>\\<p>u=t^2\\</p>\\<p>\mbox{d}u=2t\mbox{d}t\\</p>\\<p>\frac{1}{2}\int{\frac{\left(u+4\right)^2}{u\left(u^2-4u+16\right)}\mbox{d}u}\\</p>\\<p>\frac{1}{2}\int{\frac{u^2+8u+16}{u\left(u^2-4u+16\right)}\mbox{d}u}\\</p>\\<p>\frac{1}{2}\int{\frac{u^2-4u+16+12u}{u\left(u^2-4u+16\right)}\mbox{d}u}\\</p>\\<p>\frac{1}{2}\left(\int{\frac{\mbox{d}u}{u}}+\int{\frac{12}{u^2-4u+16}\mbox{d}u}\right)\\</p>\\<p>\frac{1}{2}\left(\int{\frac{\mbox{d}u}{u}}+\int{\frac{12}{\left(u-2\right)^2+12}\mbox{d}u}\right)\\</p>\\<p>\int{\frac{12}{\left(u-2\right)^2+12}\mbox{d}u}\\</p>\\<p>u-2=2\sqrt{3}v\\</p>\\<p>\mbox{d}u=2\sqrt{3}\mbox{d}v\\</p>\\<p>24\sqrt{3}\int{\frac{\mbox{d}v}{12v^2+12}}\\</p>\\<p>2\sqrt{3}\int{\frac{\mbox{d}v}{v^2+1}}\\</p>\\<p>\frac{1}{2}\left(\ln{\left|u\right|}+2\sqrt{3}\arctan{\left(\frac{u-2}{2\sqrt{3}}\right)}\right)\\</p>\\<p>\ln{\left|t\right|}+\sqrt{3}\arctan{\left(\frac{t^2-2}{2\sqrt{3}}\right)}\\</p>\\<p>\ln{\left|\tan{\left(x\right)}+\sqrt{\tan^{2}{\left(x\right)}+4}\right|}+\sqrt{3}\arctan{\left(\frac{1+\tan^{2}{\left(x\right)}+\tan{\left(x\right)}\sqrt{\tan^{2}{\left(x\right)}+4}}{\sqrt{3}}\right)}+C\\</p>\\<p>

Można było jednym podstawieniem, te pozostałe podstawienia są tylko dla wygody 

 


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#129232 Równanie różniczkowe

Napisane przez Mariusz M w 21.04.2017 - 12:16

Można też skorzystać z podanej postaci czynnika całkującego

 

\mu=\mu\left[\omega\left(x,y\right)\right]\\<br>\\P=P\left(x,y\right)\\<br>\\Q=Q\left(x,y\right)\\<br>\\\frac{\partial \mu P}{\partial y}=\frac{\partial \mu Q}{\partial x}\\<br>\\\frac{\partial \mu}{\partial y}P+\mu\frac{\partial P}{\partial y}=\frac{\partial \mu}{\partial x}Q+\mu\frac{\partial Q}{\partial x}\\<br>\\\frac{\partial \mu}{\partial y}P-\frac{\partial \mu}{\partial x}Q=\mu\frac{\partial Q}{\partial x}-\mu\frac{\partial P}{\partial y}\\<br>\\\frac{\partial \mu}{\partial y}P-\frac{\partial \mu}{\partial x}Q=\mu\left(\frac{\partial Q}{\partial x}-\frac{\partial P}{\partial y}\right)\\<br>\\\frac{\mbox{d}\mu}{\mbox{d}\omega}\cdot\frac{\partial \omega}{\partial y}P-\frac{\mbox{d}\mu}{\mbox{d}\omega}\cdot\frac{\partial \omega}{\partial x}Q=\mu\left(\frac{\partial Q}{\partial x}-\frac{\partial P}{\partial y}\right)\\<br>\\\frac{\mbox{d}\mu}{\mbox{d}\omega}\left(\frac{\partial \omega}{\partial y}P-\frac{\partial \omega}{\partial x}Q\right)=\mu\left(\frac{\partial Q}{\partial x}-\frac{\partial P}{\partial y}\right)\\<br>\\\frac{\mbox{d}\mu}{\mu}=\frac{\frac{\partial Q}{\partial x}-\frac{\partial P}{\partial y}}{\frac{\partial \omega}{\partial y}P-\frac{\partial \omega}{\partial x}Q}\mbox{d}\omega\\<br>\\\frac{\frac{\partial Q}{\partial x}-\frac{\partial P}{\partial y}}{\frac{\partial \omega}{\partial y}P-\frac{\partial \omega}{\partial x}Q}=\varphi\left(\omega\right)\\<br>\\\frac{\mbox{d}\mu}{\mu}=\varphi\left(\omega\right)\mbox{d}\omega<br>\\


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#129199 Całaka 14

Napisane przez Mariusz M w 04.04.2017 - 22:53

\int{\sqrt{1-x^2}\arcsin{x}\mbox{d}x}=\int{\frac{1-x^2}{\sqrt{1-x^2}}\arcsin{x}\mbox{d}x}\\</p>\\<p>=\int{\frac{\arcsin{x}}{\sqrt{1-x^2}}\mbox{d}x}+\int{\frac{-x}{\sqrt{1-x^2}}\left(x\arcsin{x}\right)\mbox{d}x}\\</p>\\<p>=\int{\frac{\arcsin{x}}{\sqrt{1-x^2}}\mbox{d}x}+x\sqrt{1-x^2}\arcsin{x}-\int{\sqrt{1-x^2}\left(\arcsin{x}+\frac{x}{\sqrt{1-x^2}}\right)\mbox{d}x}\\</p>\\<p>\int{\sqrt{1-x^2}\arcsin{x}\mbox{d}x}=\int{\frac{\arcsin{x}}{\sqrt{1-x^2}}\mbox{d}x}+x\sqrt{1-x^2}\arcsin{x}-\int{\sqrt{1-x^2}\arcsin{x}\mbox{d}x}-\int{x\mbox{d}x}\\</p>\\<p>2\int{\sqrt{1-x^2}\arcsin{x}\mbox{d}x}=\frac{1}{2}\arcsin^2{x}+x\sqrt{1-x^2}\arcsin{x}-\frac{1}{2}x^2+C\\</p>\\<p>\int{\sqrt{1-x^2}\arcsin{x}\mbox{d}x}=\frac{1}{4}\arcsin^2{x}+\frac{1}{2}x\sqrt{1-x^2}\arcsin{x}-\frac{1}{4}x^2+C\\</p>\\<p>


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#129198 Całka 18

Napisane przez Mariusz M w 04.04.2017 - 20:03

Dosyć dobry efekt daje pierwsze podstawienie Eulera ale jak to modnie jest unikać tych podstawień 

 

\int{\frac{5x^2-2x+10}{\sqrt{3x^2-5x+8}}\mbox{d}x}\\</p>\\<p>\sqrt{3}\int{\frac{5x^2-2x+10}{\sqrt{9x^2-15x+24}}\mbox{d}x}\\</p>\\<p>\sqrt{9x^2-15x+24}=t-3x\\</p>\\<p>9x^2-15x+24=t^2-6tx+9x^2</p>\\<p>-15x+24=t^2-6tx\\</p>\\<p>6tx-15x=t^2-24\\</p>\\<p>x\left(6t-15\right)=t^2-24\\</p>\\<p>x=\frac{t^2-24}{6t-15}\\</p>\\<p>t-3x=\frac{6t^2-15t-3t^2+72}{6t-15}=\frac{3t^2-15t+72}{6t-15}\\</p>\\<p>\mbox{d}x=\frac{2t\left(6t-15\right)-6\left(t^2-24\right)}{\left(6t-15\right)^2}\mbox{d}t\\</p>\\<p>\mbox{d}x=\frac{6t^2-30t+144}{\left(6t-15\right)^2}\mbox{d}t\\</p>\\<p>\sqrt{3}\int{\left(5\frac{\left(t^2-24\right)^2}{\left(6t-15\right)^2}-2\frac{t^2-24}{6t-15}+10\right)\frac{6t-15}{3t^2-15t+72}\cdot\frac{2\left(3t^2-15t+72\right)}{\left(6t-15\right)^2}\mbox{d}t}\\</p>\\<p>\sqrt{3}\int{\left(\frac{5\left(t^4-48t^2+576\right)-2\left(t^2-24\right)\left(6t-15\right)+10\left(36t^2-180t+225\right)}{\left(6t-15\right)^2}\right)\cdot\frac{2}{6t-15}\mbox{d}t}\\</p>\\<p>2\sqrt{3}\int{\frac{5t^4-240t^2+2880-2\left(6t^3-15t^2-144t+360\right)+360t^2-1800t+2250}{\left(6t-15\right)^3}\mbox{d}t}\\</p>\\<p>2\sqrt{3}\int{\frac{5t^4-240t^2+2880-12t^3+30t^2+288t-720+360t^2-1800t+2250}{\left(6t-15\right)^3}\mbox{d}t}\\</p>\\<p>2\sqrt{3}\int{\frac{5t^4-12t^3+150t^2-1512t+4410}{\left(6t-15\right)^3}\mbox{d}t}\\</p>\\<p>\frac{2\sqrt{3}}{27}\int{\frac{5t^4-12t^3+150t^2-1512t+4410}{\left(2t-5\right)^3}\mbox{d}t}\\</p>\\<p>-\frac{\sqrt{3}}{54}\int{\left(5t^4-12t^3+150t^2-1512t+4410\right)\frac{\left(-4\right)}{\left(2t-5\right)^3}\mbox{d}t}\\</p>\\<p>-\frac{\sqrt{3}}{54}\left(\frac{5t^4-12t^3+150t^2-1512t+4410}{\left(2t-5\right)^2}-\int{\frac{20t^3-36t^2+300t-1512}{\left(2t-5\right)^2}\mbox{d}t}\right)\\</p>\\<p>-\frac{\sqrt{3}}{54}\left(\frac{5t^4-12t^3+150t^2-1512t+4410}{\left(2t-5\right)^2}+\int{\left(10t^3-18t^2+150t-756\right)\frac{\left(-2\right)}{\left(2t-5\right)^2}\mbox{d}t}\right)\\</p>\\<p>-\frac{\sqrt{3}}{108}\left(\frac{10t^4-24t^3+300t^2-3024t+8820}{\left(2t-5\right)^2}+\frac{20t^3-36t^2+300t-1512}{2t-5}-\int{\frac{60t^2-72t+300}{2t-5}\mbox{d}t}\right)\\</p>\\<p>-\frac{\sqrt{3}}{108}\left(\frac{10t^4-24t^3+300t^2-3024t+8820}{\left(2t-5\right)^2}+\frac{20t^3-36t^2+300t-1512}{2t-5}-\int{\left(30t+39\right)\mbox{d}t}-\int{\frac{495}{2t-5}\mbox{d}t}\right)\\</p>\\<p>-\frac{\sqrt{3}}{108}\left(\frac{10t^4-24t^3+300t^2-3024t+8820}{\left(2t-5\right)^2}+\frac{20t^3-36t^2+300t-1512}{2t-5}-15t^2-39t-\frac{495}{2}\ln{\left|2t-5\right|}\right)+C\\</p>\\<p>


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#129197 Całka 23, Ostrogradskiego można

Napisane przez Mariusz M w 04.04.2017 - 19:22

Jeśli chodzi o zalety metody Ostrogradskiego to nie wymaga ona rozkładu mianownika na czynniki

co pozwoli zredukować jego stopień

Aby uzyskać mianowniki wystarczy policzyć NWD\left(M(x),M'(x)\right)

algorytmem kolejnych dzieleń

Jeżeli mamy podany rozkład mianownika na czynniki to zalety stosowania metody Ostrogradskiego ujawniają się gdy

mianownik ma wielokrotne pierwiastki zespolone


  • 1


#129196 Całka pierwiastek

Napisane przez Mariusz M w 04.04.2017 - 12:59

\int{x^{\frac{1}{3}}\left(7-3x^2\right)^{\frac{1}{3}}\mbox{d}x}\\</p>\\<p>m=\frac{1}{3}\\</p>\\<p>n=2\\</p>\\<p>p=\frac{1}{3}\\</p>\\<p>\frac{m+1}{n}=\frac{2}{3}\\</p>\\<p>\frac{m+1}{n}+p=1 \in \mathbb{Z}\\</p>\\<p>t^3=\frac{7-3x^2}{x^2}</p>\\<p>


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#129117 Rozwiąż równanie różnicowe

Napisane przez Mariusz M w 19.03.2017 - 04:58

y_{n+2}-4y_{n+1}+4y_{n}=0 \qquad y_{0}=3\\y_{1}=2\\</p>\\<p>y_{n}-4y_{n-1}+4y_{n-2}=0 \qquad y_{0}=3\\y_{1}=2\\</p>\\<p>y_{n}=4y_{n-1}-4y_{n-2}=0 \qquad y_{0}=3\\y_{1}=2\\</p>\\<p>Y\left(t\right)=\sum_{n=0}^{\infty}y_{n}t^n\\</p>\\<p>\sum_{n=2}^{\infty}y_{n}t^{n}=\sum_{n=2}^{\infty}4y_{n-1}t^n+\sum_{n=2}^{\infty}{-4y_{n-2}t^n}\\</p>\\<p>\sum_{n=2}^{\infty}y_{n}t^{n}=4t\sum_{n=2}^{\infty}y_{n-1}t^{n-1}-4t^2\sum_{n=2}^{\infty}{y_{n-2}t^{n-2}}\\</p>\\<p>\sum_{n=2}^{\infty}y_{n}t^{n}=4t\sum_{n=1}^{\infty}y_{n}t^{n}-4t^2\sum_{n=0}^{\infty}{y_{n}t^{n}}\\</p>\\<p>\sum_{n=0}^{\infty}y_{n}t^{n}-3-2t=4t\left(\sum_{n=0}^{\infty}y_{n}t^{n}-3\right)-4t^2\sum_{n=0}^{\infty}{y_{n}t^{n}}\\</p>\\<p>Y\left(t\right)-3-2t=4tY\left(t\right)-12t-4t^2Y\left(t\right)\\</p>\\<p>Y\left(t\right)\left(1-4t+4t^2\right)=-10t+3\\</p>\\<p>Y\left(t\right)=\frac{-10t+3}{\left(1-2t\right)^2}\\</p>\\<p>Y\left(t\right)=\frac{5-10t-2}{\left(1-2t\right)^2}\\</p>\\<p>Y\left(t\right)=\frac{5}{1-2t}-\frac{2}{\left(1-2t\right)^2}\\</p>\\<p>\sum_{n=0}^{\infty}2^{n}t^n=\frac{1}{1-2t}\\</p>\\<p>\frac{\mbox{d}}{\mbox{d}t}\left(\sum_{n=0}^{\infty}2^{n}t^n\right)=\frac{\mbox{d}}{\mbox{d}t}\left(\frac{1}{1-2t}\right)\\</p>\\<p>\sum_{n=0}^{\infty}n2^{n}t^{n-1}=-\frac{1}{\left(1-2t\right)^2}\cdot\left(-2\right)\\</p>\\<p>\sum_{n=1}^{\infty}n2^{n}t^{n-1}=\frac{2}{\left(1-2t\right)^2}\\</p>\\<p>\sum_{n=0}^{\infty}\left(n+1\right)2^{n+1}t^{n}=\frac{2}{\left(1-2t\right)^2}\\</p>\\<p>\sum_{n=0}^{\infty}\left(n+1\right)2^{n}t^{n}=\frac{1}{\left(1-2t\right)^2}\\</p>\\<p>Y\left(t\right)=\sum_{n=0}^{\infty}5\cdot 2^{n}t^{n}-2\sum_{n=0}^{\infty}\left(n+1\right)2^{n}t^n\\</p>\\<p>y_{n}=5\cdot 2^{n}-2\left(n+1\right)\cdot 2^{n}\\</p>\\<p>y_{n}=\left(3-2n\right)\cdot 2^{n}</p>\\<p>


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#129062 Całka 29

Napisane przez Mariusz M w 05.03.2017 - 06:11

Proponuję rozbić na dwie całki  w jednej licznik skróci się z mianownikiem a drugą można będzie policzyć całkując przez części

 

\int{\frac{x^3}{\left(x^2+x+25\right)^2}\mbox{d}x}=-\frac{1}{198}\int{\frac{x^2+x+25}{\left(x^2+x+25\right)^2}\mbox{d}x}+\frac{1}{198}\int{\left(99x^2-49x+25\right)\cdot\frac{2x+1}{\left(x^2+x+25\right)^2}\mbox{d}x}\\</p>\\<p>\int{\frac{x^3}{\left(x^2+x+25\right)^2}\mbox{d}x}=-\frac{1}{198}\int{\frac{1}{\left(x^2+x+25\right)}\mbox{d}x}+\frac{1}{198}\int{\left(99x^2-49x+25\right)\cdot\frac{2x+1}{\left(x^2+x+25\right)^2}\mbox{d}x}\\</p>\\<p>

 

Najpierw całkujemy przez części a później dodajemy całki

 

Przydatne będzie też podstawienie x+\frac{1}{2}=\frac{3}{2}\sqrt{11}t

 

Jak znalazłem ten rozkład ?

 

Podzieliłem licznik przez pochodną trójmianu kwadratowego z mianownika

Otrzymałem  resztę która była stałą, do tej stałej dodałem i odjąłem taki składnik aby otrzymać postać kanoniczną trójmianu kwadratowego z mianownika

 

\int{\frac{x^3}{\left(x^2+x+25\right)^2}\mbox{d}x}=-\frac{1}{198}\int{\frac{x^2+x+25}{\left(x^2+x+25\right)^2}\mbox{d}x}+\frac{1}{198}\int{\left(99x^2-49x+25\right)\cdot\frac{2x+1}{\left(x^2+x+25\right)^2}\mbox{d}x}\\</p>\\<p>\int{\frac{x^3}{\left(x^2+x+25\right)^2}\mbox{d}x}=-\frac{1}{198}\int{\frac{1}{\left(x^2+x+25\right)}\mbox{d}x}+\frac{1}{198}\int{\left(99x^2-49x+25\right)\cdot\frac{2x+1}{\left(x^2+x+25\right)^2}\mbox{d}x}\\</p>\\<p>\int{\frac{x^3}{\left(x^2+x+25\right)^2}\mbox{d}x}=-\frac{1}{198}\int{\frac{1}{\left(x^2+x+25\right)}\mbox{d}x}-\frac{1}{198}\frac{99x^2-49x+25}{x^2+x+25}+\frac{1}{198}\int{\frac{198x-49}{x^2+x+25}\mbox{d}x}\\</p>\\<p>\int{\frac{x^3}{\left(x^2+x+25\right)^2}\mbox{d}x}=-\frac{1}{198}\frac{99x^2-49x+25}{x^2+x+25}+\frac{1}{99}\int{\frac{99x-25}{x^2+x+25}\mbox{d}x}\\</p>\\<p>\frac{1}{99}\int{\frac{99x-25}{x^2+x+25}\mbox{d}x}=\frac{1}{99}\int{\frac{99x-25}{\left(x+\frac{1}{2}\right)^2+\frac{99}{4}}\mbox{d}x}\\</p>\\<p>x+\frac{1}{2}=\frac{3}{2}\sqrt{11}t\\</p>\\<p>\mbox{d}x=\frac{3}{2}\sqrt{11}\mbox{d}t\\</p>\\<p>\frac{\sqrt{11}}{66}\int{\frac{99\left(\frac{3}{2}\sqrt{11}t-\frac{1}{2}\right)-25}{\frac{99}{4}t^2+\frac{99}{4}}\mbox{d}t}\\</p>\\<p>\frac{\sqrt{11}}{66}\int{\frac{\frac{297}{2}\sqrt{11}t-\frac{149}{2}}{\frac{99}{4}t^2+\frac{99}{4}}\mbox{d}t}\\</p>\\<p>\frac{\sqrt{11}}{4 \cdot 33}\cdot\frac{4}{99}\int{\frac{297\sqrt{11}t-149}{t^2+1}\mbox{d}t}\\</p>\\<p>\frac{297\cdot 11}{3267}\int{\frac{t}{t^2+1}\mbox{d}t}-\frac{149\sqrt{11}}{3267}\int{\frac{1}{t^2+1}\mbox{d}t}\\</p>\\<p>=\int{\frac{t}{t^2+1}\mbox{d}t}-\frac{149\sqrt{11}}{3267}\int{\frac{1}{t^2+1}\mbox{d}t}\\</p>\\<p>=\frac{1}{2}\ln{\left|t^2+1\right|}-\frac{149\sqrt{11}}{3267}\arctan{\left(t\right)}+C\\</p>\\<p>\frac{1}{2}\ln{\left|x^2+x+25\right|}-\frac{149\sqrt{11}}{3267}\arctan{\left(\frac{\sqrt{11}}{33}\left(2x+1\right)\right)}+C\\</p>\\<p>\int{\frac{x^3}{\left(x^2+x+25\right)^2}\mbox{d}x}=-\frac{1}{198}\frac{99x^2-49x+25}{x^2+x+25}+\frac{1}{2}\ln{\left|x^2+x+25\right|}-\frac{149\sqrt{11}}{3267}\arctan{\left(\frac{\sqrt{11}}{33}\left(2x+1\right)\right)}+C\\</p>\\<p>

 

 

Wynik można jeszcze uprościć dzieląc licznik przez mianownik

 

 

Można też liczyć sposobem podanym przez Ostrogradskiego

 

\int{\frac{x^3}{\left(x^2+x+25\right)^2}\mbox{d}x}=\frac{a_{1}x+a_{0}}{x^2+x+25}+\int{\frac{b_{1}x+b_{0}}{x^2+x+25}\mbox{d}x}\\</p>\\<p>\frac{x^3}{\left(x^2+x+25\right)^2}=\frac{a_{1}\left(x^2+x+25\right)-\left(a_{1}x+a_{0}\right)\left(2x+1\right)}{\left(x^2+x+25\right)^2}+\frac{b_{1}x+b_{0}}{x^2+x+25}\\</p>\\<p>\frac{x^3}{\left(x^2+x+25\right)^2}=\frac{a_{1}\left(x^2+x+25\right)-\left(a_{1}x+a_{0}\right)\left(2x+1\right)+\left(b_{1}x+b_{0}\right)\left(x^2+x+25\right)}{\left(x^2+x+25\right)^2}\\</p>\\<p>x^3=a_{1}\left(x^2+x+25\right)-\left(a_{1}x+a_{0}\right)\left(2x+1\right)+\left(b_{1}x+b_{0}\right)\left(x^2+x+25\right)\\</p>\\<p>x^3=a_{1}x^2+a_{1}x+25a_{1}-2a_{1}x^2-a_{1}x-2a_{0}x-a_{0}+b_{1}x^3+b_{1}x^2+25b_{1}x+b_{0}x^2+b_{0}x+25b_{0}\\</p>\\<p>x^3=b_{1}x^3+\left(b_{1}+b_{0}-a_{1}\right)x^2+\left(25b_{1}+b_{0}-2a_{0}\right)x+25b_{0}+25a_{1}-a_{0}\\</p>\\<p>\begin{cases}b_{1}=1\\b_{0}=a_{1}-1\\24+a_{1}=2a_{0}\\100a_{1}-50-24-a_{1}=0\end{cases}\\</p>\\<p>\begin{cases}b_{1}=1\\\b_{0}=a_{1}-1\\24+a_{1}=2a_{0}\\99a_{1}=74\end{cases}\\</p>\\<p>\begin{cases}b_{1}=1\\99b_{0}=-25\\99a_{0}=1225\\99a_{1}=74\end{cases}\\</p>\\<p>\int{\frac{x^3}{\left(x^2+x+25\right)^2}\mbox{d}x}=\frac{1}{99}\frac{74x+1225}{x^2+x+25}+\frac{1}{99}\int{\frac{99x-25}{x^2+x+25}\mbox{d}x}\\</p>\\<p>\frac{1}{99}\int{\frac{99x-25}{x^2+x+25}\mbox{d}x}=\frac{1}{99}\int{\frac{99x-25}{\left(x+\frac{1}{2}\right)^2+\frac{99}{4}}\mbox{d}x}\\</p>\\<p>x+\frac{1}{2}=\frac{3}{2}\sqrt{11}t\\</p>\\<p>\mbox{d}x=\frac{3}{2}\sqrt{11}\mbox{d}t\\</p>\\<p>\frac{\sqrt{11}}{66}\int{\frac{99\left(\frac{3}{2}\sqrt{11}t-\frac{1}{2}\right)-25}{\frac{99}{4}t^2+\frac{99}{4}}\mbox{d}t}\\</p>\\<p>\frac{\sqrt{11}}{66}\int{\frac{\frac{297}{2}\sqrt{11}t-\frac{149}{2}}{\frac{99}{4}t^2+\frac{99}{4}}\mbox{d}t}\\</p>\\<p>\frac{\sqrt{11}}{4 \cdot 33}\cdot\frac{4}{99}\int{\frac{297\sqrt{11}t-149}{t^2+1}\mbox{d}t}\\</p>\\<p>\frac{297\cdot 11}{3267}\int{\frac{t}{t^2+1}\mbox{d}t}-\frac{149\sqrt{11}}{3267}\int{\frac{1}{t^2+1}\mbox{d}t}\\</p>\\<p>=\int{\frac{t}{t^2+1}\mbox{d}t}-\frac{149\sqrt{11}}{3267}\int{\frac{1}{t^2+1}\mbox{d}t}\\</p>\\<p>=\frac{1}{2}\ln{\left|t^2+1\right|}-\frac{149\sqrt{11}}{3267}\arctan{\left(t\right)}+C\\</p>\\<p>\frac{1}{2}\ln{\left|x^2+x+25\right|}-\frac{149\sqrt{11}}{3267}\arctan{\left(\frac{\sqrt{11}}{33}\left(2x+1\right)\right)}+C\\</p>\\<p>\int{\frac{x^3}{\left(x^2+x+25\right)^2}\mbox{d}x}=\frac{1}{99}\frac{74x+1225}{x^2+x+25}+\frac{1}{2}\ln{\left|x^2+x+25\right|}-\frac{149\sqrt{11}}{3267}\arctan{\left(\frac{\sqrt{11}}{33}\left(2x+1\right)\right)}+C\\</p>\\<p>


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#129051 Całka 24

Napisane przez Mariusz M w 03.03.2017 - 08:31

\int{\frac{\mbox{d}x}{\left(x^2+x+1\right)\sqrt{x^2+x-1}}}\\</p>\\<p>\sqrt{x^2+x-1}=t-x\\</p>\\<p>x^2+x-1=t^2-2tx+x^2\\</p>\\<p>x-1=t^2-2tx\\</p>\\<p>2tx+x=t^2+1\\</p>\\<p>x\left(2t+1\right)=t^2+1\\</p>\\<p>x=\frac{t^2+1}{2t+1}\\</p>\\<p>t-x=\frac{2t^2+t-t^2-1}{2t+1}=\frac{t^2+t-1}{2t+1}\\</p>\\<p>x^2+x+1=\frac{t^4+2t^2+1+2t^3+t^2+2t+1+4t^2+4t+1}{\left(2t+1\right)^2}\\<br>\\x^2+x+1=\frac{t^4+2t^3+7t^2+6t+3}{\left(2t+1\right)^2}\\</p>\\<p>\mbox{d}x=\frac{2t\left(2t+1\right)-2\left(t^2+1\right)}{\left(2t+1\right)^2}\mbox{d}t\\</p>\\<p>\mbox{d}x=\frac{2t^2+2t-2}{\left(2t+1\right)^2}\mbox{d}t\\</p>\\<p>\int{\frac{\left(2t+1\right)^2}{t^4+2t^3+7t^2+6t+3}\cdot\frac{2t+1}{t^2+t-1}\cdot\frac{2\left(t^2+t-1\right)}{\left(2t+1\right)^2}\mbox{d}t}\\</p>\\<p>\int{\frac{4t+2}{t^4+2t^3+7t^2+6t+3}\mbox{d}t}=\int{\frac{4t+2}{\left(t^2+t+3-\sqrt{6}\right)\left(t^2+t+3+\sqrt{6}\right)}\mbox{d}t}\\</p>\\<p>=\int{\frac{\sqrt{6}}{6}\left(\frac{2t+1}{t^2+t+3-\sqrt{6}}-\left(\frac{2t+1}{t^2+t+3-\sqrt{6}}\right)\right)\mbox{d}t}\\</p>\\<p>=\frac{\sqrt{6}}{6}\int{\frac{2t+1}{t^2+t+3-\sqrt{6}}\mbox{d}t}-\frac{\sqrt{6}}{6}\int{\frac{2t+1}{t^2+t+3+\sqrt{6}}\mbox{d}t}\\</p>\\<p>=\frac{\sqrt{6}}{6}\ln{\left|\frac{t^2+t+3-\sqrt{6}}{t^2+t+3+\sqrt{6}}\right|}+C</p>\\<p>


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