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Question-128093




Question Number 128093 by BHOOPENDRA last updated on 04/Jan/21
Answered by Dwaipayan Shikari last updated on 04/Jan/21
L(e^(2t) +4t^3 −2sin3t+3cos3t)  =∫_0 ^∞ e^(2t−st) +∫_0 ^∞ 4t^3 e^(−st) +i∫_0 ^∞ e^(3it−st) −e^(−3it−st) +(3/2)∫_0 ^∞ e^(3it−st) +e^(−3it+st)   =(1/(s−2))+(4/s^4 )∫_0 ^∞ u^3 e^(−u) +i((1/(s−3i))−(1/(s+3i)))+(3/2)((1/(s−3i))+(1/(s+3i)))  =(1/(s−2))+((4Γ(4))/s^4 )−(6/(s^2 +9))+((3s)/(s^2 +9))=(1/(s−2))+((24)/s^4 )+((3(s−2))/(s^2 +9))
$$\mathscr{L}\left({e}^{\mathrm{2}{t}} +\mathrm{4}{t}^{\mathrm{3}} −\mathrm{2}{sin}\mathrm{3}{t}+\mathrm{3}{cos}\mathrm{3}{t}\right) \\ $$$$=\int_{\mathrm{0}} ^{\infty} {e}^{\mathrm{2}{t}−{st}} +\int_{\mathrm{0}} ^{\infty} \mathrm{4}{t}^{\mathrm{3}} {e}^{−{st}} +{i}\int_{\mathrm{0}} ^{\infty} {e}^{\mathrm{3}{it}−{st}} −{e}^{−\mathrm{3}{it}−{st}} +\frac{\mathrm{3}}{\mathrm{2}}\int_{\mathrm{0}} ^{\infty} {e}^{\mathrm{3}{it}−{st}} +{e}^{−\mathrm{3}{it}+{st}} \\ $$$$=\frac{\mathrm{1}}{{s}−\mathrm{2}}+\frac{\mathrm{4}}{{s}^{\mathrm{4}} }\int_{\mathrm{0}} ^{\infty} {u}^{\mathrm{3}} {e}^{−{u}} +{i}\left(\frac{\mathrm{1}}{{s}−\mathrm{3}{i}}−\frac{\mathrm{1}}{{s}+\mathrm{3}{i}}\right)+\frac{\mathrm{3}}{\mathrm{2}}\left(\frac{\mathrm{1}}{{s}−\mathrm{3}{i}}+\frac{\mathrm{1}}{{s}+\mathrm{3}{i}}\right) \\ $$$$=\frac{\mathrm{1}}{{s}−\mathrm{2}}+\frac{\mathrm{4}\Gamma\left(\mathrm{4}\right)}{{s}^{\mathrm{4}} }−\frac{\mathrm{6}}{{s}^{\mathrm{2}} +\mathrm{9}}+\frac{\mathrm{3}{s}}{{s}^{\mathrm{2}} +\mathrm{9}}=\frac{\mathrm{1}}{{s}−\mathrm{2}}+\frac{\mathrm{24}}{{s}^{\mathrm{4}} }+\frac{\mathrm{3}\left({s}−\mathrm{2}\right)}{{s}^{\mathrm{2}} +\mathrm{9}} \\ $$
Commented by BHOOPENDRA last updated on 04/Jan/21
thankyou
$${thankyou} \\ $$

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