A meta point about economics: there is almost always a way to argue both ways in theory, especially if you use enough "links". It's more true for variables like exchange rates, which are subject to multiple factors. It's really hard to pinpoint exact cause-and-effect relationships in economics because nothing is really "ceteris paribus" in real life, and it also depends on the time period in which you look at it.
That being said, the main way that people argue that an increase in interest rates leads to an appreciation is asset attractiveness point i.e. higher interest rates means Australian assets are more attractive which leads to an increase in the demand for Australian dollars to purchase such assets.
The "more overseas borrowing" point is harder to argue, because more borrowing from overseas actually increases demand for AUD because once you borrowed in the foreign currency, you would need to convert it to AUD to use it, which increases demand for AUD.
The argument of "higher interest rates → more investment in Australia → greater NPY deficit → larger CAD → lower investor confidence → lower demand for AUD → depreciation" is probably a bit too indirect.
(The below information is not in the HSC syllabus but nice to know)
However... in practice, when the cash rate increases, the exchange rate doesn't appreciate noticeably. You can go and check yourself by looking at:
For example, on 7 June 2023, the cash rate increased by 0.25%, but actually after the 2:30pm announcement, AUDUSD depreciates immediately after, but then recovers back after a day or so.
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It's outside the scope of the syllabus to explain the exact micro movements of the exchange rate, but one reason why it doesn't hold up in practice is because the cash rate change is already "priced in" - that is, people already expected the cash rate to rise so they already acted on the decision before the actual cash rate change announcement. This is a reflection of the efficient market hypothesis. Another possible reason is that markets are irrational and react to unexpected news. For example, many investors did not expect the cash rate to increase in Australia in the June meeting, and the surprise may have caused a minor sell-off in the currency.