Imagine this, my baby brother was making annoying weird noise to irritate me, so I'd tell him
"Can you NOT do that!" {But here I can't say "CAN'T you do that!"}
Now,imagine my big brother was making me to go to the store just after I entered the house from school,so I'd tell him
"CAN'T you do that!" {But here I can't say "Can you NOT do that!"}
But the grammar rules state that if "not" isn't contracted then it must come after the subject but in these cases it obviously makes notable difference. What are the present rules to this and what should I generally use in modern times? Also I have seen this in archaic/older English, what were the older grammar rules when it came to negatives?