He has yet to finish his homework, has/hasn't he?

Either one could be used, depending on the circumstances.

Thank you.

"Doesn't he? " would have sounded better.

Those little questions (isn't he, don't they, etc) which follow a statement in that type of sentence are called 'question tags'.

There are three types:

1. A positive statement followed by a negative question tag:

These are used when the questioner requires assurance or confirmation that the statement is correct (the questioner hopes, suspects or expects this).

He is twenty-five years old, isn't he?
They are all drunk, aren't they?
I will be paid this week, won't I?

2. A negative statement followed by a positive question tag:

These are generally used when the questioner is surprised or doubtful.

He isn't twenty-five years old, is he? (Perhaps he looks younger or older).
They aren't all drunk, are they? (They are a disgrace!)
I won't be paid this week, will I? (I fear I will not)

3. A positive statement followed by a positive question tag:

These are used when we want to express emotion such as disbelief, suspicion, shock, anger, sarcasm, strong interest and so on.

So, they are getting married, are they? That’s great news! (note: this expresses strong interest with some surprise)

You think you’re funny, do you? Well, I don’t! (note: this expresses sarcasm)

You can run faster than me, can you? Let’s have a race then! (note: this expresses disbelief)

He’s going to do it today, is he? He has been saying that for weeks! (note: this expresses sarcasm and disbelief)

So, you are sorry now, are you? Well, you should have said so much earlier. (note: this expresses anger)

We also use POSITIVE STATEMENT + POSITIVE QUESTION TAG sometimes when we are making suggestions. Listen to these examples, paying particular attention to intonation:

Let’s go to the park, shall we?

We will write to him today, shall we? (note: in both these examples, the tag ‘shall’ is used, as it is the ‘suggestion’ modal)

Finally, we use POSITIVE STATEMENT + POSITIVE QUESTION TAG when there is a ‘hidden negative’ in the statement. Look at these examples:

Nothing is better than this, is it? (note: here, ‘nothing’ is a negative subject of the verb, so we use a positive question tag because the statement is actually a negative statement. Other negative subjects are: no-one, nobody, and so on. )

You hardly know him, do you? (note: here, ‘hardly’ means ‘almost not’, so it gives the verb a negative meaning. Other adverbs like this are: scarcely, barely, rarely and never.)

Hi centrox,

On second thoughts, could you illustrate the difference between the following sentences?

He has yet to finish his homework, has he?
He has yet to finish his homework, hasn't he?

Thanks.

The first expresses impatience and/or disbelief, the second is a simple enquiry.

Thanks, centrox.