\def\rload{R_{\rm load}} \input ../format \titlesub{Part 3: Executive Summary}{Mystery Circuit} \input ../com \section{Matrix Representation} To determine the relevant properties of the linear system, matrix form is useful (this form was chosen to reduce fractions' usage): \def\x{{\bf x}} $$\x' = {1\over R_1C_1C_2\rload} \pmatrix{0&-C_2\rload &0 \cr 0&-C_2(R_1+\rload)&-C_1R_1\cr 0&C_2R_1 &-C_1R_1} \x + {1\over R_1} \pmatrix{\omega\cos(\omega t)\cr \omega\cos(\omega t)\cr 0} .$$ The characteristic polynomial is $$-\lambda( (-\lambda-C_2(R_1+\rload))(-\lambda-C_1R_1) + C_2C_1R_1^2).$$ Expanded, $$-\lambda( \lambda^2 + \lambda(C_2(R_1+\rload)+C_1R_1) + C_1C_2R_1(2R_1+\rload)).$$ In terms of its roots (with $b=C_2(R_1+\rload)+C_1R_1$ and $c = C_1C_2R_1(2R_1+\rload),$ $$-\lambda{(\lambda-{-b+\sqrt{b^2-4c}\over2}) (\lambda-{-b-\sqrt{b^2-4c}\over 2})}$$ %For reference, %$$b^2-4c = C_2^2(R_1+\rload)^2 + C_1^2\rload^2 % - 2C_1C_2\rload(3R_1+\rload).$$ Let $r_1$ and $r_2$ designate these two non-zero roots. \def\bu{\par\leavevmode\llap{\hbox to \parindent{\hfil $\bullet$ \hfil}}} \noindent The eigenvalues and respective eigenvectors are: \bu $\lambda_1 = 0, v_1 = \pmatrix{1\cr0\cr0}$ \bu $\lambda_2 = {r_1\over C_1C_2R_1\rload}, v_2 = ??$ \bu $\lambda_3 = {r_2\over C_1C_2R_1\rload}, v_3 = ??$ \section{Nonhomogenous System} Extending to the nonhomogenous system, \bye