#!/usr/bin/env python w = 100 # May vary c1 = 2.5*10**(-6) c2 = 1*10**(-6) r1 = 200 rload = 1000 a = 1 b = c1*r1*rload + r1*c2*rload + (rload**2)*c2 c = rload det = (b**2-4*a*c)**(1/2) r1 = (-b-det)/(2*a) r2 = (-b+det)/(2*a) A = c1*c2*rload**2*w*(rload-w**2)/(b**2*w**2 + rload**2 - 2*rload*w**2 + w**4) B = b*c1*c2*rload**2*w**3/(b**2*w**2 + rload**2 - 2*rload*w**2 + w**4) C = - c1*c2*rload**2*w*(rload-w**2)/(b**2*w**2 + rload**2 - 2*rload*w**2 + w**4) D = - b*c1*c2*rload**3*w/(b**2*w**2 + rload**2 - 2*rload*w**2 + w**4) # from https://www.wolframalpha.com/input/?i=solve+for+x1%2Cx2%2Cx3%2Cx4+in+%7B%7B1%2C0%2C1%2C0%7D%2C+%7Bb%2C1%2C0%2C1%7D%2C+%7BR%2C+b%2C+w%5E2%2C+0%7D%2C+%7B0%2C+R%2C+0%2C+w%5E2%7D%7D*%7Bx1%2Cx2%2Cx3%2Cx4%7D+%3D+%7B0%2C0%2Cw*c_1*c_2*R%5E2%2C0%7D and an insane partial fraction decomposition E = (D-C*r1)/(r2-r1) F = C - E # Another PFD of Cs-D/(as^2+bs+c) G = B/w # Final solution should be # Gsin(theta) + Bcos(theta) + Ee^(r1 t) + Fe^(r2 t) # But E, F, r1, and r2 are complex. Luckily, conjugates make it that # = 2e^(Re(r1) t) ( Re(E)cos(Im(r1)t) - Im(E)sin(Im(r1)t) ) rer1 = r2.real reE = F.real imr1 = r2.imag imE = F.imag # switched because positive ones were needed print("%.2E * sin(theta) + %.2E * cos(theta) + 2e^(%.2f t) (%.2E cos(%.2f t) - %.2E sin(%.2f t))" % (G, B, rer1, reE, imr1, imE, imr1))