I'm trying to define a function g(x)=sum(frac(jp/q),j,0,x) where p,q are pre-defined constants (say (p,q)=(33,21)). Sage did not give any errors, but when I type g(10), I would get output symbolic expression sum(frac(11/7j), j, 0, 10), which is different from the expected value 31/7.
How do I fix this?