I get the error "Undefined function 'symsum' for input arguments of type 'double'. while solving the equation given below.Please help me.

clc
clear all
syms m x k 
m=5;
k=2;
alpha=2;
beta=(1.65)*(10^(-5));
sai=10;
rho=15;
pt=2;
pn=16.56*10^(-14);
g = @(x)symsum((((1/factorial(k))*(m*sai*pn/2*beta)^k)),k,0,m-1).*exp(-(rho.*x)+((m*sai*pn*x.^alpha)/(beta*pt)))*x.^(alpha*1);
format long
f= rho*integral(g,0,inf)
plot(alpha,f,'*')

[Star Strider]

This runs without error and then yields an infinite result:

syms m x k 
m=sym(5);
% k=sym(2);
alpha=sym(2);
beta=sym(1.65E-5);
sai=sym(10);
rho=sym(15);
pt=sym(2);
pn=sym(16.56E-14);
g = symsum((((1/factorial(k))*(m*sai*pn/2*beta)^k)),k,0,m-1).*exp(-(rho.*x)+((m*sai*pn*x.^alpha)/(beta*pt)))*x.^(alpha*1);
f= rho*int(g,x,0,inf)
plot(alpha,f,'*')

I leave the rest to you.

[Walter Roberson]

In particular you had

syms k
k=2

But the second line removes the identity of k as a symbolic variable

[PARVEEN KUMAR SINGHAL]

Thankyou Very Much Sir. Really it solved my problem.

Answer 1

[Cameron B]

I ran the script below and got a very large answer. You should check my code/output as there may be a mistake (using matlab mobile and don’t have time to check it), but at least there’s no error.

    clc
clear all
syms k x
m=5;
alpha=2;
beta=(1.65)*(10^(-5));
sai=10;
rho=15;
pt=2;
pn=16.56*10^(-14);
c=(m*sai*pn)/(beta*pt);
fun=exp(-1.*(rho.*x + c.*x.^alpha)).*x.^(alpha*k);
g = symsum(1/factorial(k).*c.^k.*rho.*int(fun,0,inf),k,0,m-1);
g=double(g);