"Students, have you noted down the lecture?"
Translation:Студенты, вы записали лекцию?
It's not wrong, it should be accepted, too. Use the Report button next time you get this sentence.
No, this is not a phrase I have ever used as a native (US) speaker. I'm not sure what it would mean. Maybe you would note down the time and place of an upcoming lecture so you wouldn't forget it? If you wanted to write down what was said during a lecture, you would "take notes on the lecture" (copy down the important parts) or "copy down the lecture" (copy everything).
No, it's not wrong. This sentence certainly sounds OK with «студентки» too (for example, when a professor adresses a group of female students).
How am i supposed to know it's студенты and not ученики?
is it because of the "lecture" ? Like, classes in high school are not to be called "lectures" or so? if so nice move but I'm learning a language here and not running my grey cells to work as Sherlock Holmes you know. Спасибо
Yes, it's accusative.
Feminine singular noun in -я and -а have a separate accusative form (-ю and -у respectively), that is different both from nominative and genitive.
All the other nouns use the rule you've described (accusative = nominative for inanimate, accusative = genitive for animate), and even the plural лекции would use this rule, but in singular, they have a special form.
(A few masculine nouns like папа 'Dad', дядя 'uncle', Дима 'Dima (short form of Dmitry)' are declined as if they are feminine. Those also would have a special accusative form: папу, дядю, Диму.)
I'll concede that some English speakers may think "have you noted down the lecture" sounds reasonable, and I'll also concede that this odd phrase is indeed decipherable by those for whom it sounds odd. But in American English, "have you taken notes on the lecture" (or "did you take notes on the lecture?") are how this would be said, with very limited exception.
I'd love to know if "noted down" is a primary means of saying this in other English speaking countries, but regardless, I think "take notes on" variants make the most sense to use for this exercise, as I suspect this would be clearer in other parts of the world than "noted down" is to American English speakers.