Input to num2str must be numeric.

clc;
disp('a')
syms H zeta
omega = 1;
solve(H == 1/sqrt((1-omega^2)^2 + (2*zeta*omega)^2),zeta);

H = [10 5 2.66 1 0.5];

for i=1:5
    zetas(i) = 1/(2*H(i));
end

disp([' Damping Factor for system 1 = ' num2str(zetas(1)) ''])
disp([' Damping Factor for system 2 = ' num2str(zetas(2)) ''])
disp([' Damping Factor for system 3 = ' num2str(zetas(3)) ''])
disp([' Damping Factor for system 4 = ' num2str(zetas(4)) ''])
disp([' Damping Factor for system 5 = ' num2str(zetas(5)) ''])

disp('----------------x---------------')
disp('b')
clear omega
syms omega
for i=1:3
    omegas = solve(1 == 1/sqrt((1-omega^2)^2 + (2*zetas(i)*omega)^2));
    omega_star(i) = max(omegas);
end

disp([' Omeaga* for system 1 = ' num2str(omega_star(1)) ''])
disp([' Omeaga* for system 2 = ' num2str(omega_star(2)) ''])
disp([' Omeaga* for system 3 = ' num2str(omega_star(3)) ''])
Getiing error for num2str(omega_star).... Input to num2str must be numeric.
 It works for the disp([' Damping Factor for system 1 = ' num2str(zetas(1)) ''])

Answer 1

[madhan ravi]

Use double() because omega_star is of symbolic class , ofcourse it can be acheived using fprintf() or sprintf()

num2str(double(omega_star(1))) % do the same for the rest

[Abhinay Tadwalkar]

Thanks, I had got answer last time without using double(). I am confused

[Abhinay Tadwalkar]

For num2str(zetas(1)) there is no double() still it works. How come?

[madhan ravi]

because it's of type double by nature , by default solve() returns the answer with symbolic class not of type double , you can always check the class of the variable using whos

whos zetas  % it will return type double
whos omega_star %it will return type sym

[Salvatore Veneruso]

ok

Answer 2

[Steven Lord]

I would consider using string in this case, as that can convert either numeric or symbolic expressions to text.

H = [10 5 2.66 1 0.5];
zetas = sym(1)./(2*H);
whos H zetas

  Name       Size            Bytes  Class     Attributes

  H          1x5                40  double              
  zetas      1x5                 8  sym                 

fprintf("H: %s.\n", string(H))

H: 10.
H: 5.
H: 2.66.
H: 1.
H: 0.5.

fprintf("zetas: %s.\n", string(zetas))

zetas: 1/20.
zetas: 1/10.
zetas: 25/133.
zetas: 1/2.
zetas: 1.