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Solve-Equation-dx-t-dt-2x-t-y-t-dy-t-dt-3y-t-x-1-t-y-1-t-2-1-0-3-x-t-y-t-A-2-1-0-3-det-A-E-0-det-2-1-




Question Number 219996 by SdC355 last updated on 04/May/25
Solve Equation  ((dx(t))/dt)=2x(t)+y(t)  ((dy(t))/dt)=−3y(t)   (((x^((1)) (t))),((y^((1)) (t))) )= ((2,(    1)),(0,(−3)) ) (((x(t))),((y(t))) )  A= ((2,(    1)),(0,(−3)) )  det{A−𝛌E}=0  det{ ((2,(    1)),(0,(−3)) )− ((𝛌,0),(0,𝛌) )}=0  𝛌=2,−3  v_1 = (((−1)),((    5)) )  v_2 = ((1),(0) )   ((x),(y) )=C_1 e^(λt) v_1 +C_2 e^(λt) v_2 = (((−1),1),((    5),0) ) (((C_1 e^(2t) )),((C_2 e^(−3t) )) )   ((x),(y) )= (((−C_1 e^(2t) +C_2 e^(−3t) )),((       5C_1 e^(2t) )) )  ((dx(t))/dt)=−2C_1 e^(2t) −3C_2 e^(−3t) ≠  2x(t)+y(t)=−2C_1 e^(2t) −2C_2 e^(−3t) +5C_1 e^(2t)   ((dy(t))/dt)=10e^(2t) ≠  −3y(t)=−15C_2 e^(2t)    Wrong..... Help
$$\mathrm{Solve}\:\mathrm{Equation} \\ $$$$\frac{\mathrm{d}{x}\left({t}\right)}{\mathrm{d}{t}}=\mathrm{2}{x}\left({t}\right)+{y}\left({t}\right) \\ $$$$\frac{\mathrm{d}{y}\left({t}\right)}{\mathrm{d}{t}}=−\mathrm{3}{y}\left({t}\right) \\ $$$$\begin{pmatrix}{{x}^{\left(\mathrm{1}\right)} \left({t}\right)}\\{{y}^{\left(\mathrm{1}\right)} \left({t}\right)}\end{pmatrix}=\begin{pmatrix}{\mathrm{2}}&{\:\:\:\:\mathrm{1}}\\{\mathrm{0}}&{−\mathrm{3}}\end{pmatrix}\begin{pmatrix}{{x}\left({t}\right)}\\{{y}\left({t}\right)}\end{pmatrix} \\ $$$$\mathrm{A}=\begin{pmatrix}{\mathrm{2}}&{\:\:\:\:\mathrm{1}}\\{\mathrm{0}}&{−\mathrm{3}}\end{pmatrix} \\ $$$$\mathrm{det}\left\{\mathrm{A}−\boldsymbol{\lambda}\mathrm{E}\right\}=\mathrm{0} \\ $$$$\mathrm{det}\left\{\begin{pmatrix}{\mathrm{2}}&{\:\:\:\:\mathrm{1}}\\{\mathrm{0}}&{−\mathrm{3}}\end{pmatrix}−\begin{pmatrix}{\boldsymbol{\lambda}}&{\mathrm{0}}\\{\mathrm{0}}&{\boldsymbol{\lambda}}\end{pmatrix}\right\}=\mathrm{0} \\ $$$$\boldsymbol{\lambda}=\mathrm{2},−\mathrm{3} \\ $$$$\boldsymbol{\mathrm{v}}_{\mathrm{1}} =\begin{pmatrix}{−\mathrm{1}}\\{\:\:\:\:\mathrm{5}}\end{pmatrix} \\ $$$$\boldsymbol{\mathrm{v}}_{\mathrm{2}} =\begin{pmatrix}{\mathrm{1}}\\{\mathrm{0}}\end{pmatrix} \\ $$$$\begin{pmatrix}{{x}}\\{{y}}\end{pmatrix}={C}_{\mathrm{1}} {e}^{\lambda{t}} \boldsymbol{\mathrm{v}}_{\mathrm{1}} +{C}_{\mathrm{2}} {e}^{\lambda{t}} \boldsymbol{\mathrm{v}}_{\mathrm{2}} =\begin{pmatrix}{−\mathrm{1}}&{\mathrm{1}}\\{\:\:\:\:\mathrm{5}}&{\mathrm{0}}\end{pmatrix}\begin{pmatrix}{{C}_{\mathrm{1}} {e}^{\mathrm{2}{t}} }\\{{C}_{\mathrm{2}} {e}^{−\mathrm{3}{t}} }\end{pmatrix} \\ $$$$\begin{pmatrix}{{x}}\\{{y}}\end{pmatrix}=\begin{pmatrix}{−{C}_{\mathrm{1}} {e}^{\mathrm{2}{t}} +{C}_{\mathrm{2}} {e}^{−\mathrm{3}{t}} }\\{\:\:\:\:\:\:\:\mathrm{5C}_{\mathrm{1}} {e}^{\mathrm{2}{t}} }\end{pmatrix} \\ $$$$\frac{\mathrm{d}{x}\left({t}\right)}{\mathrm{d}{t}}=−\mathrm{2}{C}_{\mathrm{1}} {e}^{\mathrm{2}{t}} −\mathrm{3}{C}_{\mathrm{2}} {e}^{−\mathrm{3}{t}} \neq \\ $$$$\mathrm{2}{x}\left({t}\right)+{y}\left({t}\right)=−\mathrm{2}{C}_{\mathrm{1}} {e}^{\mathrm{2}{t}} −\mathrm{2}{C}_{\mathrm{2}} {e}^{−\mathrm{3}{t}} +\mathrm{5}{C}_{\mathrm{1}} {e}^{\mathrm{2}{t}} \\ $$$$\frac{\mathrm{d}{y}\left({t}\right)}{\mathrm{d}{t}}=\mathrm{10}{e}^{\mathrm{2}{t}} \neq \\ $$$$−\mathrm{3}{y}\left({t}\right)=−\mathrm{15}{C}_{\mathrm{2}} {e}^{\mathrm{2}{t}} \\ $$$$\:\mathrm{Wrong}…..\:\mathrm{Help} \\ $$
Answered by MrGaster last updated on 04/May/25

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