How could I solve this error?

this code does not have any problem with respect to r and t, but when I add interval for t and r it gives this error

thanks for helping

B=(2/pi)^(1/2);
r1=0.00001;
k=0.42;
Cp=3600;
g=1000;
rho=1048;
Tb=37;
qm=300;
w=0.0005;
ra=0.01;

%%

c=w*rho*Cp; 

r_distance=ra*2; 
time_total=1; 
dr=r_distance/10; 
dt=0.1;
rmesh=0:dr:r_distance; 
tmesh=0:dt:time_total; 
rskip=2;
tskip=2;
number_iterations=2; 
nr=length(rmesh);
nt=length(tmesh);
V=zeros(nt,nr);
for i=1:nt
 for j=1:nt
   
     for m=1:number_iterations
 q = int((((B*(rp*sqrt(c))^(-0.5)*sin(rp*sqrt(c))/(sqrt(rp)*B*(sqrt(c))^(-0.5)*sin(sqrt(c)))))-1)*rp*sin(m*pi*rp),rp,0,1); % the integral r prime from 0 to 1
      
      first_term = symsum((exp((m*pi)^2+c)*(-tmesh(j)))*sin(m*pi*rmesh(i))*q, m, 1, 10); % a summation
     end
end
 end

Error using sym/symsum (line 52)
Cannot compute the sum with respect to '1'. The summation index must be a symbolic variable.

Error in test (line 36)
      first_term = symsum((exp((m*pi)^2+c)*(-tmesh(j)))*sin(m*pi*rmesh(i))*q, m, 1, 10); % a summation

[darova]

You don't have any symbolic variables. Why don't just use sum?

[Bajdar Nouredine]

dear @darova I used sum because I have summuation in the equation

here is the equation , my aim is solve this equation for different r and t

[darova]

You have to declare m as symbolic variable

syms m

[Bajdar Nouredine]

@darova I tried , same error occured

[darova]

Here is the problem: oyu are using the same variable

[Bajdar Nouredine]

@darova it solved, thanks,

[darova]

Answer 1

[darova]

You are using the same variable as in for loop. That why you have an error