when the word could and would used?

Question

help me with honest ans!
example please.

Answer 1

Could refers to capability. Would refers to intent.

Could you have eaten all that by yourself?
Would you have eaten all that by yourself?

Answer 2

Theoretically speaking, could and would are in the subjunctive mood.

They are not always used 'correctly' but it may be useful to know things such as:

Would you ever shut up! Is technically wrong, but widely used and very expressive. It doesn't say what it seems to say - Would you stop talking (IF I were to pay you money, promise to leave, ....)

There seems to always be an implicit if when would is used in sentences like this. Ignore that and use it anyway. Otherwise, you would be the only English speaker in the world trying to make this distinction.

Could and would are used to make requests extra polite (or grovelling). Could / Would you give me a loan of 10,000 please?
In this case I would recommend "Could", because it comes across as more friendly.

Would can be used to give orders or commands, but not as sharply as without it. e.g.
Would you have that report on my desk by 9.30 on Friday?

Would is also used incorrectly in court. This is probably to evade as much as possible directly answering any questions:
Invented example:
Question: Did you drink alcoholic drink?
Answer: Well, I would drink Budweiser on occasions.

Answer 3

Cellee Dub is right.

Do you want to do it? (Do you have the will to do it?) = would
Is it possible? Is it within your power? = could

I'd really like you help you, but I can't. I would if I could.

Answer 4

This link is a good one for your question...

Answer 5

could you please help me? could infers is it possible for someone to help. would you please help me? would asks if one would do it, give help, assuming they could.