Register to reply 
MATLABfinding roots and summations 
Share this thread: 
#1
Sep710, 09:11 PM

P: 2

1. The problem statement, all variables and given/known data
(all this is included in the attachment, btw) p(z)=z^4+4.25*z^2+1 1. use matlab to find the four roots Ck of p(z)= 0 2. For all complex constants ck (different than Ck) define the complex valued function Z(t)= 4[tex]\Sigma[/tex]k=1 ck*exp(Ck*t) ^^that is a sigma sign with variable k going from one to four 2. Relevant equations p(z)=z^4+4.25*z^2+1 a=4.25 3. The attempt at a solution Number 1 I can do fine, my code is as follows: >> syms x >> y=(x^4+4.25*x^2+1) >> >> solve (y) ans = (2)*i 2*i i/2 i/2 The problem is when I get to problem 2, because I have just about no idea of how to compute a sum in matlab. I've tried a for loop with k going from one to for, after naming each of the roots C1, C2, C3, C4. Also, I'm having some trouble figuring out what it means by 'complex constants ck'.. sorry i'm not much help in understanding this haha. 3 and 4 i think I can figure out Any help would be very much appreciated 


#2
Sep710, 09:21 PM

P: 1,875

I don't do much with symbolic in Matlab, but something like this should work.
>> syms x >> y=(x^4+4.25*x^2+1) >> roots = solve (y) Z=0; syms t for j=1:length(roots) Z = Z + roots(j)*exp(roots(j)*t) end 


Register to reply 
Related Discussions  
Matlab:Chapra , ROOTS [ Bracketing Method] Help needed.  Math & Science Software  7  
Finding roots with MATLAB  General Math  1  
Finding roots  Calculus & Beyond Homework  0  
Matlab  ODE, find roots of the characteristic equation for the natural response  Calculus & Beyond Homework  4  
Finding the roots  Calculus  4 