If aimed at a single person - perhaps so. But in that case "Вас" should be capitalised (although this rule is not always followed). Uncapitalised "вас" should refer to a group of people, and as such "благодарю вас" is a fairly common way of e.g. thanking your audience.
She is absolutely correct. In the synodical text of the Orthodox Bible благодать is connected to the word grace in English as in "By grace you have been saved unto eternal life and not by works lest any man should boast... or Grace and Peace to you all from God our Father and the Lord Jesus Christ..." Saint Paul Holy Apostle. Each morning in our prayers ,we Orthodox believers thank God that He has not destroyed us because of our sins. When I buy a булочка на улицу I say, "Спасибо." Но когда я упал в кразне плошеде ближке Казански Собор и крове от моего роты пришел я сказал, "благодарю вас," к люди которие помогали мне! I hope this helps. Grace - Бпагодать and Peace to you all. ALL THE BEST IN YOUR STUDIES.
Yes. Благодарю Вас, with the Bac capitalized has always been the more formal phrase. The literal “I thank you” isn’t a good translation. I was always taught that it’s more like thank you (very much) even though very much isn’t the literal meaning. If they have a problem with this, they need to refer to The Defense Language Institute, at Monterey, California.
Yes, it is rather formal but not necessarily more polite, rather slightly reserved, especially its shortened form 'Благодарю', which is way more popular anyway. And when the feeling of gratitude is deep and sincere (intonation will tell it), the phrase is closer to 'I appreciate it'.
Accusative is the form the nouns, adjectives and pronons take to represent the object of the verbs. Exemple: I see YOU. "You" here is the object. In russian it would be translated as ВАС.
Genitive case is the form the nouns, adjectives and pronouns take to tho say who is the owner of a thing. Ex. What is YOUR name. Here "your" is like the russian genitive case.
The prepositional case is the form the noun, adjective and pronouns take when they are with a preposition. Exemple: I am with YOU. Here "you" would work like the russian prepositional case.
I am not sure why you insist that both exact meanings and grammatical structures should be a perfect match between different languages. "Благодарю" is a bit more formal than mere "Thanks" (while "Благодарю Вас" is even more formal). Hence I do not think that translating "Благодарю" as "Thank you" is completely unreasonable. "Благодарю Вас", being more formal, could be translated as "Thank you very much indeed" or something like that -- meaning-wise, not structure-wise.
Perhaps you haven't noticed the number of comments on DL (for the Russian lessons, at least) regarding literal vs. equivalent(?) translations, and how helpful transliterations would be if they were provided. For example, "У меня есть..." translates to "I have..." but the literal translation is "By me there is...". The latter is very helpful for actually understanding the grammatical structure (in the negative as well) as opposed to rote memorization. By the same token, being presented with Благодарю as translating to "Thank you" and Благодарю вас as also translating to "Thank you", in the absence of any translational insights, is confusing and yes, appears redundant.
No. Вас is simply a genitive, accusative or prepositional form of Вы. (In this particuar example, it's accusative since it's a direct object of the verb "благодарить"="to thank".)
Now, Вы is either a formal singular you or a plural you regardless of formality. Strictly speaking, formal singular Вы should be capitalised while plural вы isn't, but many native speakers ignore this rule and do not capitalise вы regardless of its specific meaning.
If it helps, Russian is quite similar to German here:
Tы = du
Вы = Sie/ihr.