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Three solutions of a second-order linear equation L[y] = g(t) are ψ1(t)=3et+et2,ψ2(t)=7et+et2\psi_{1}(t)=3 e^{t}+e^{t^{2}}, \psi_{2}(t)=7 e^{t}+e^{t^{2}} and ψ3(t)=5et+et3+et2.\psi_{3}(t)=5 e^{t}+e^{-t^{3}}+e^{t^{2}}. Find the solution of the initial-value problem L[y]=g;y(0)=1,y(0)=2.L[y]=g ; \quad y(0)=1, \quad y^{\prime}(0)=2.

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The general equation [1]:L[y]=d2ydt2+p(t)dydt+q(t)y[1]L[y]=g(t)=d2ydt2+p(t)dydt+q(t)yThree solutions of a second-order linear equation [1] are:ψ1(t)=3et+et2ψ2(t)=7et+et2ψ3(t)=5et+et3+et2is a solution corresponding homogenous equation:ψ2(t)ψ1(t)=4etψ3(t)ψ2(t)=et32ety(t)=4c1et+c2(et32et)+et2is the general solution.\begin{align*} \textbf{The general equation [1]:}\\ L[y]&=\dfrac{d^{2}y}{dt^{2}}+p(t)\dfrac{dy}{dt}+q(t)y \dots \text{[1]}\\\\ L[y]&=g(t)\\&=\dfrac{d^{2}y}{dt^{2}}+p(t)\dfrac{dy}{dt}+q(t)y\\\\ \textbf{Three solutions of a second-order linear equation [1] are:}\\ \psi_{1}(t)&=3e^{t}+e^{t^{2}}\\ \psi_{2}(t)&=7e^{t}+e^{t^{2}}\\ \psi_{3}(t)&=5e^{t}+e^{-t^{3}}+e^{t^{2}}\\ \textbf{is a solution corresponding homogenous equation:}\\ \psi_{2}(t)-\psi_{1}(t)&=4e^{t}\\ \psi_{3}(t)-\psi_{2}(t)&=e^{-t^{3}}-2e^{t}\\\\ \Rightarrow y(t)&=4c_{1}e^{t}+c_{2}(e^{-t^{3}}-2e^{t})+e^{t^{2}}\\ \textbf{is the general solution.}\\\\ \end{align*}

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