Write an equivalent expression in relational algebra for the following sql query?
select p. name, c. name
from professor p, course c, taught t
where p. id = t. profid and t. semester = 's2002'
and t. crscode = c. crscode

Consider the series where in this problem you must attempt to use the ratio test to decide whether the series converges. compute enter the numerical value of the limit l if it converges, inf if it diverges to infinity, minf if it diverges to negative infinity, or div if it diverges but not to infinity or negative infinity.