Two questions about the Ukrainian course...
1) What are the differences between "і", "та" and "а"?
2) How do I type the letter ґ? I have installed the Ukrainian keyboard, and when I open the on-screen keyboard, there is the ґ in the place of the ''z'' key. But when I press ''z'' it instead types ''я''. EDIT: Nevermind about this question, I've made a custom keyboard layout for Ukrainian and included the missing ґ. :)
і and та are mostly interchangeable. We have both for euphony. For example you wouldn't want to use i before a word that also starts from i as it would be hard to pronounce. Та also can be used as a synonym to але (but). A is used when you want to express contrast (similar to while, whereas): Це яблуко зелене, а це - жовте (This apple is green, and (while) this one is yellow).
2) I don’t have an answer to that question, but note that the Duolingo course will not use the ґ letter at all, so you don’t have to worry too much about not being able to type it.
йцукенгшщзхї фівапролджє ячсмитьбю. ґ Oh, I found it on my Microsoft Ukrainian keyboard: I must hold down the right ALT key and while holding it, press U key. Looking back, I see that Stecchetto gave the same information. and that you said it didn't work. I am sorry that it didn't work for you.