MATLAB: What’s the program mistake

symbolic variable

clear all
clc;
syms a b c 
w=zeros(3,1);
w(1,1)=3*a+b;
w(2,1)=b+2;
w(3,1)=c-a;
disp(w)
b=3;
disp(w)

Best Answer

w = sym(zeros(3,1))

You preallocated w as a numeric type and then tried to stuff a sym into it. If you preallocate w as a symbolic, it works as expected.

Related Solutions

MATLAB: Solve symbol four equations for c1 c2 c3 c4

Thanks, I solve it,

clc
clear
syms a b x y c1 c2 c3 c4 T1 T2 T3 T4  
T=c1+c2*x+c3*y+c4*x*y;
%%
r1=c1+c2*a+c3*b+c4*a*b-T1;
r2=c1-c2*a+c3*b-c4*a*b-T2;
r3=c1-c2*a-c3*b+c4*a*b-T3;
r4=c1+c2*a-c3*b-c4*a*b-T4;
%%Find C1 and C4
p13=r1+r3;
p24=r2+r4;
n1=solve(p13==0,c1);
n2=solve(p24==0,c1);
C4=solve(n1==n2,c4)
w1=solve(p13==0,c4);
w2=solve(p24==0,c4);
C1=solve(w1==w2,c1)
r1=subs(r1,c1,C1);
r1=subs(r1,c4,C4);
r2=subs(r2,c1,C1);
r2=subs(r2,c4,C4);
r3=subs(r3,c1,C1);
r3=subs(r3,c4,C4);
r4=subs(r4,c1,C1);
r4=subs(r4,c4,C4);
%%Find C3
q12=r1+r2;
q34=r3+r4;
C3=solve(q12==0,c3)
r1=subs(r1,c3,C3);
r2=subs(r2,c3,C3);
r3=subs(r3,c3,C3);
r4=subs(r4,c3,C3);
%% find C2
C2=solve(r1==0,c2)
r1=subs(r1,c2,C2);
r2=subs(r2,c2,C2);
r3=subs(r3,c2,C2);
r4=subs(r4,c2,C2);
C1
C2
C3
C4

MATLAB: How to write code for hankle and toeplitz matrix

My apologies! I was not thinking clearly when I wrote the nonsensical A.^(0:9). The following should produce the desired two arrays.

   M = 6;  % A is M x M, B is M x 1, C is 1 x M
   N = 10;
   F = zeros(N+1,M);
   F(1,:) = C;
   for k = 2:N+1
     F(k,:) = F(k-1,:)*A;
   end
   r = F(1:N,:)*B;
   c = [C*B;zeros(M-1,1)];
   phi = toeplitz(r,c);
   F = F(2:N+1,:);

Best Answer

Related Solutions

MATLAB: Solve symbol four equations for c1 c2 c3 c4

MATLAB: How to write code for hankle and toeplitz matrix

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