Create and assign variable in function

Hello I have a function and I pass in a row vector with different values and I want to take those values and assign variables that I use throughout my function to those specific values and also make them global to be used in other functions

examples

function [] = example1(theta)
if (nargin<1)
    theta = zeros(1,28)
    sym('j%d',size(theta)%I also tried genvarname({'j'})
   for i=1:length(theta)
       j{i} = theta(i);
   end
else 
    sym('j%d',size(theta)%I also tried genvarname({'j'})
   for i=1:length(theta)
       j{i} = theta(i);
   end
end

global j1 j2 ....j28 %is there a better way to do this line?

j1 
j2 
.
.
j28

When I run the function it says that j1-j28 are undefined, what I am expecting is it to print out j1 = 0 -j28 = 0 if I didn't put in any arguments and j1 = 5 - j28 = 7 if I entered values in for theta

and also I want to be able to use j1-j28 in another function

function exmaple2()
plot(sin(j1))
end