writing out equation in matlab with summation.

I am trying to solve a simultaneous equation in MATLAB and to write this function down I needed to use symsum.

So for example I have code similar to this:

syms k d(k)

symsum(d(k),1,10) = d(1)+d(2)+...+d(10)

Where the d(k)'s are supposed to be a vector of eigenvalues that I have computed before but once d(k) has been written as a symbolic function then I lose the eigenvalues stored in the vector d. Is there a way aroudn this problem as I cannot seem to find one in MATLAB.