Literally: "Please show understanding", which also makes sense in English.
Can you generally use zeigen in this way in German? Like, to outwardly make a characteristic visible? Showing gratitude, showing boredom, showing displeasure, etc?
Yes, but it's almost never used in spoken language.
"Sie zeigte ihre Dankbarkeit" (or "sie zeigte sich dankbar") = "she showed her gratitude"
"Die Schüler zeigten ihre Langeweile deutlich" = "the students openly displayed their boredom"
etc. I've added a second example to the first sentence, because next to showing something, you can also show yourself to be a certain way ("sich zeigen"), but that does get very stuffy very quickly. It works for simple sentences like the first but even with an extra adjective like in the second example, re-writing it into "die Schüler zeigten sich..." felt weird.
The Duden has some more examples (under 4 a) and 4 c), quite far down): http://www.duden.de/rechtschreibung/zeigen
Ok, others have reported that that exact translation is not accepted [EDIT: It is now!]. Is there a difference of meaning? I would say that "please be understanding" and "please show understanding" are slightly different, with emphasis on "showing" understanding if you use that sentence. But then, Duo is currently insisting the opposite. Before reporting it, can you confirm this?
[EDIT: See my comment below to 'Fuzzymurrey'. I still think this should be accepted, but the difference of meaning is apparently not there in German.]
If it is almost never used, what would be used instead in for "please be understanding?"
Yes. That is another sentence using the Imperativ mood, which is used for commands. The imperative mood can be constructed in a couple of ways - including the one Duolingo chose, and this one here which is the polite form.
can someone explain why is the verb in 1st person if im reffering to a second person, please (you) show understanding, shouldnt it then be, bitte zeigst verstandnis? is it some other form or tense other than present? what am i missing
It does now! I met this sentence in "Feelings", quite a while after "Infinitives" (May 5th 2019)
But then "Verständnis" is a noun, and "understanding" in "please be understanding" is an adjective, so they are still structurally different, no?
I answered "Please show understanding" also. Is there a reason that it is wrong, or should it be reported?
[EDIT: It is accepted now.]
After discussing with a native-speaker, I still think it should be accepted. This sentence would be used for example on a sign when there is an inconvenience: "The toilet is closed. Please show understanding".
That said, it doesn't explicitly mean the understanding must be outwardly shown like I explained is the case in English in another comment. It's just somewhat idiomatic to mean "Please be understanding". Using zeigen (in the imperative) just allows Verständnis ("understanding") to be used as a noun. The literal translation of "Please be understanding" would be Bitte sei verständnisvoll, which requires the adjective form of "understanding", verständnisvoll. This isn't obvious in English as "understanding" is both a noun and adjective.
But from the discussion I had, it seems that Duo's phrasing is more common.
I translated it as Please show understanding and it marked me wrong. This is frustrating. Zeigen is show, ja?
Here's an example: You are the boss of a company, and ten people work for you. But the company doesn't have enough money, and you cannot pay all your workers. You decide to tell one worker that he can not work for you anymore, so that you can afford to pay the others next month. Your worker will probably be sad that he lost his job, and might get angry. But if you say "please show understanding", you are asking him to understand your reason, and to not get angry.
"I understand" = In my head, I know your reason.
"I show understanding" = Because I understand your reason, I act calm.
The meaning is between those two I mentioned. You understand, and it affects your actions, but it's maybe not so obvious.
"Please show understanding" was accepted when I did this exercise. I think it is a more accurate translation than "Please be understanding". The speaker does not merely want me to understand. She wants me to show that I understand.
I feel like a more natural translation would be 'please understand' because nobody really says please be understanding.
I'd rather saying the translation is something like "Please show understanding"
"Please show some understanding" sounds more natural in English and should be accepted, no? English frequently inserts "some" where German has a noun without an article.