Let ()=9(5)^6+6(5)^4

Find the local extrema of .f.

(Use symbolic notation and fractions where needed. Give your answer in the form of a commaseparated list of point coordinates in the form (,) Enter DNE if the function has no local extrema.)

Determine the intervals on which is concave up and on which it is concave down.

(Use symbolic notation and fractions where needed. Give your answers as intervals in the form (,). Use the symbol for infinity, for combining intervals, and parenthesis "(", ")" for open intervals. Enter if the interval isempty.)

Find any points of inflection.

(Use symbolic notation and fractions where needed. Give your answer in the form of a commaseparated list of point coordinates in the form (,). Enter DNE if the function has no points of inflection.)