Use the Ratio Test to determine the radius of convergence of Un . 4" Then determine whether the series converges at the endpoints and find the interval of convergence if possible. (Use symbolic notation and fractions where needed. Give your answers as intervals in the form (*,*). Use the symbol co for infinity, U for combining intervals, and an appropriate type of parenthesis "(", ")", "[" or "]" depending on whether the interval is open or closed. Enter DNE if interval is empty.) XE