#!/usr/bin/env python import matplotlib.pyplot as plt import tkinter from math import sin,cos,e from sys import argv def f(x): return G*sin(A*x) + B*cos(B*x) + 2*e**(rer1 * x) * (reE * cos(imr1 * x) - imE * sin(imr1 * x)) for w in range(100,10000,100): 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 = A/w # Final solution should be # Gsin(A * theta) + Bcos(B * 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(%.2E t) + %.2E * cos(%.2E t) + 2e^(%.2f t) (%.2E cos(%.2f t) - %.2E sin(%.2f t))" % (G, A, B, B, rer1, reE, imr1, imE, imr1)) x = [] y = [] for i in range(1000): x.append(i/100) y.append(f(i/100)) plt.plot(x,y) if len(argv) > 1 and argv[1] == 'img': plt.savefig('plot.png') else: plt.show()