get the combination of instructions used in the finite product and infinite product of the sequence

A、symskn;P=symprod(1+1/k^3,k,1,n);P=simplify(P);
B、symsk;P=symprod(1+1/k^3,k,1,inf);P=simplify(P);
C、symsnx;s=symsum(2/((2*n+1)*(2*x+1)^(2*n+1)),n,0,inf);simplify(s);
D、symsxy;f=x*cos(y);F=taylor(f,[x,y],[a,b],’Order’,4)