I have Maple 11.01 and Im doing simple taylor and series commands. Perhaps I'm doing something wrong but I cant figure out what it is. This is my problem:

f := arctan(3*x);
taylor(f,x=0,3);


and the output from the function is: 3*x+O(x^3) but my "Texas Instruments TI-89 Titanium" and the "Maple TA" website say that the correct answer is 3*x-9*x^3