Discussion in 'Math' started by shaider530, Jul 9, 2007.
4i + 8 int idt - 3 di/dt = 50 cos(2t +75 degrees)
find the current?
4i + 8 idt - 3 di/dt = 50 cos(2t +75 degrees)
find the current.
are you familiar with laplace transform?
no im not familiar with laplace transform. what is that?
laplace transform is very useful for finding various parameters and solutions to complex circuits and equations.
u can get some idea abt it from here.
u may for now have to solve the above equation using solution methods for differential equations.
I think this is easiest with phasors...
4*I + (8*I)/(j*w) - 3*j*w*I = 50<75
w = omega = 2
4*I - (j*8*I)/2 - j*6*I = 50<75
add the imaginary terms
4*I - j*65*I = 50<75
convert to polar form
65.123<-86.5 * I = 50<75
divide the magnitudes and subtract the angles
I = 0.7678<161.5
i = 0.7678*cos(2t + 161.5 degrees) A
This is very similar to the Laplace transform...basically "s" becomes "jw", like Fourier. But w is constant, so it is in "phase-domain" instead of frequency-domain.
You might want to double-check my algebra/arithmetic, I'm not really that awake.