R,L,C,E0,a,b,omega,k=var('R,L,C,E0,a,b,omega,k')
S=L*omega - 1/(omega*C)
I(t)=a*cos(omega*t)+b*sin(omega*t)
I(t)=I(t).subs(a=(E0*S)/(R^2+S^2),b=(E0*R)/(R^2+S^2))
solve([L*k^2+R*k+1/C==0],k)
c1,c2,d1,d2=var('c1,c2,d1,d2')
I=c1*e^(d1*t)+c2*e^(d2*t)+ I(t)
I=I.subs(d1=-1/2*(C*R + sqrt(C^2*R^2 - 4*C*L))/(C*L),d2=-1/2*(C*R - sqrt(C^2*R^2 - 4*C*L))/(C*L))
I=I.subs(R=40,L=1/2,C=1/750,E0=25,omega=100)
print 'I is'
print I

SageDays/Kreyszig-2.12-7 (last edited 2010-08-10 13:02:24 by hardikgajera)