"Look it up in a dictionary."
Shouldnt it be じしょで if we're saying "in the dictionary"? Is hiku only used with obj+を in this context?
They are different forms of the same verb. Hiite is the imperative TE form of Hiku, Hikimasu is the masu form. The TE form donotes a request or demand, the masu form is just a modified version of the dictionary form, it's kind of a future tense but not strictly.
I look up virtually everything Duolingo teaches me on Jisho. jisho dot org, that is.
There seem to be quite a few kinks to work out in the beta form. I have a low intermediate level of Japanese, but I still encounter new words. I actually like getting the kanji because it means I can copy it and paste it into Google translate. Or as I learned from the others on this forum, you might want to try http://jisho.org. The problem with using just hirigana is you often don't know where to group the syllables.