I have a maple exercise where it ask me to find the limit of a sum, here what's I type

f:= 2*k/(2*k+11);

g:= sum(f,k=1..n);

limit(n^(11/2)*g,n=infinity);

It spit out the answer infinity

but the answer is 10395/64*Pi^(1/2), can anyone tell me what am i doing wrong