Primitives

i just don't know how to primitivize very well

what should i do when i need to primitivize a fraction

could you please explain me clearly how this function was primitivized?
http://img369.imageshack.us/img369/1093/zzzls4.jpg

>>11
Actually it isn't spelled incorrectly, it's in portuguese. You could have scrolled down to see that the text is in English.
Secondly, thanks for the diss, it really helps a lot.