I need the solutions for r1, r2 and r3 for the following voltage divider:
Hence the following eqs. system arise:
eq1=(r1+r2+r3)/(1e5+r1+r2+r3)==0.238eq2=(r2+r3)/(1e5+r1+r2+r3)==0.213eq3=(r3)/(1e5+r1+r2+r3)==0.125
1) [A,B] = equationsToMatrix([eq1,eq2,eq3], [r1,r2,r3]) gives the error: "Cannot convert to matrix form because the system does not seem to be linear." It seems linear to me, what am I missing?
2) I made step 1 by hand, and found A*X=Y leading to:
A = [-.875 -.875 .875, -.787 .787 .787, .762 .762 .762]X=[r1, r2, r3]
and
Y=[12.5e3, 21.3e3, 23.8e3]
Then linsolve(A,Y) gives:
ans =
1.0e+04 * 0.2084 0.6390 2.2760
However this answer is wrong. If I enter these values in a simulation, I don't get, i.e., 0.125*Vs over R3. What am I missing again??
3) I found the correct answer using solve instead of linsolve:
[x1, x2, x3]=solve(eq1,eq2,eq3)
Gives after vpa():
x1 = 3281x2 = 115448x3 = 16404
And those values run fine during simulation. I still don't get 1) and 2) though.
- Also seems like hitting enter while typing won't space between lines!!
Best Answer