Every time I try to write a sum or prod. in latex I get something like this: http://data.artofproblemsolving.com/...c0e633e009.png
any help on how to make the notation correct?
Every time I try to write a sum or prod. in latex I get something like this: http://data.artofproblemsolving.com/...c0e633e009.png
any help on how to make the notation correct?