Question

y''+7y'=3e^2x

помогите решить​

Answer 1

$y''+7y'=3e^{2x}\\\\1)\; \; k^2+7k=0\; \; ,\; \; k(k+7)=0\; \; ,\; \; k_1=0\; ,\; k_2=-7\\\\y_{oo}=C_1+C_2\cdot e^{-7x}\\\\2)\; \; f(x)=3e^{2x}\; \; \to \; \; \alpha =2\ne 0\ne -7\; \; \to \; \; r=0\\\\y_{chastn.}=Ae^{2x}\cdot x^0=Ae^{2x}\\\\y'=2Ae^{2x}\\\\y''=4Ae^{2x}\\\\y''+7y'=4Ae^{2x}+14Ae^{2x}=3e^{2x}\; \; ,\qquad 18Ae^{2a}=3e^{2x}\\\\18A=3\; \; \to \; \; A=\frac{1}{6}\\\\y_{chastn.}=\frac{1}{6}\cdot e^{2x}\\\\3)\; \; y_{on}=C_1+C_2e^{-7x}+\frac{1}{6}\cdot e^{2x}$