"Derivative" is not quite the right word, but ulv and lupus are probably related through descent from a language ancestral to both Danish and Latin -- ulv is from the same source as English "wolf", i.e. Proto-Indo-European wlkwo- or something like that; see http://www.etymonline.com/index.php?term=wolf . That page says that Latin lupus is "probably" from that same root.
See also https://en.wiktionary.org/wiki/ulv#Etymology and https://en.wiktionary.org/wiki/lupus#Etymology_4 . That Wiktionary page says that Latin probably did not inherit this word directly from Proto-Indo-European but borrowed it from another language which had inherited it and, through regular sound change in that language, changed the -kw- to -p-. Which would imply that the Danish and Latin words are still related ultimately but a little more fuzzily.
But the -en of the Danish definite article and the -in- of the Latin derivative ending I imagine are not related.
I actually realized something even more probable and useful. You can often drop the "W" from english and german words and end up with something similar to danish. For example (format is english, german, danish), Worm, Wurm, Orm. Word, Wort, Ord. Wolf, Wolf, olv. Wort, Wuerze, urt. That is kind of interesting, that seems to make more sense here.