i have a problem with symsum

mu = 2.7;
sigma = 1;
a =log(10)/10;
syms j r;
yf = symsum((r^-mu) , j, 1, 3)./(r^-mu);
g = symsum((r^(-2*mu))./(r^-mu).^2, j, 1, 3);
H=exp((a^2*sigma^2)./2)*(g*((exp(a^2*sigma^2)-1)+1))^-1/2;
==> the result is 3 for yf (the result take the same value of j index)
==> the result of H is  1541528098327599/9497638187650606

Any one know what is the problem here Thank you for your consideration

Answer 1

[Thorsten]

Probably the yf is wrong:

yf = symsum((r^-mu) , j, 1, 3)./(r^-mu);
==> the result is 3 for yf (the result take the same value of j index)

This doesn't make sense, because yf is just a constant, not a function of r and eta, as specified.