Does 'to' function as a preposition in 'the trick to getting this chair to fold' but as a to-infinitive in 'some tricks to speed up your ...'?

Question

In a dictionary, I find two example sentences of the use of "trick":

What's the trick to getting this chair to fold up?

On page 21, some tricks to speed up your beauty routine.

As we know, "to" can use be used as a preposition or as a word before an infinitive. When do we use it as a preposition and when as a word before an infinitive?

When "trick" can be followed by "to-infinitive" and "to" as a preposition, why is the first sentence "What is the trick to getting this chair to fold up" instead of "What is the trick to get this chair to fold up"? On the other hand, why is the second example "...some tricks to speed up your beauty routine", but not "..some tricks to speeding up your beauty routine"?

Answer 1

I've edited the title question (which appeared far too general and had been in part addressed on ELU before). There are a couple of particular usages involved in these specific examples.

'Is a trick to', like (the probably less informal) 'is a means to', can be followed by a present participial clause:

This imperative is derived from a causal 'law' ... that false promising is a means to getting ready money

[Online Guide to Ethics and Morality] ... and there are many hits on Google for "is a means to getting / achieving / making ..."

Other nouns are used in similar constructions: 'This is the key to understanding the issue.' There are over 7 million hits on Google for "is the key to understanding the".

.......

[W]hat is a trick to getting the best currency rate?

[Beth Allcock_Daily Express] ... and there are 140 000 hits on Google for "is a trick to getting".

'Is the trick to' is likewise idiomatic; for instance

Magic is the trick to understanding the mind.

[Durham University] (and 8 million hits on Google for "is the trick to").

Though modern analyses come down in favour of 'getting' in 'getting the best currency rate' (for example) being a verb (it does have a complement-or-whotsit now classed as a direct object), 'to' is classed as a preposition here.

..........................

Note that in the same Express article there is:

Brexit news: Currency expert reveals trick to avoid weak pound ...

There are a reasonable number of Google hits for "a trick to avoid having" and "a trick to speed up", over 1 1/2 million for "a trick to get", getting on for (now there's a fuzzy quantifier!) 2 million for "a trick to make" (but I expect a lot of false positives here). I'd class 'a trick to + infinitive' (and close variants like 'some tricks to') as idiomatic, given a sensible verb.

The 'to' here is the 'with the purpose/intended purpose of' [+ ing-form] usage, which I wouldn't class as the infinitive marker. The example given can be analysed as the remnant after deletion of 'On page 21, some tricks for you to speed up your beauty routine', which looks far more like a to-infinitive to usage. Compare '... a tool to extract staples with'.

Answer 2

[1] What's the trick to [getting this chair to fold up]?

[2] some tricks [to speed up your beauty routine].

If clause is of the -ing type, then the preceding "to" is a preposition, and if the clause is an infinitival then "to" is a subordinator serving as a marker within the clause.

Thus "to" is a preposition in [1] and a subordinator in [2]

Answer 3

Some nouns + get mean achieve or obtain can be used like this:

• The trick to getting this chair to fold is [x]
• The solution to getting these voters to turn out is [x]
• The answer to getting more people at the park is [x]

get x to means: to obtain or achieve or persuade

• Getting people to understand you can be difficult.
• Getting better quality/price ratios is very hard.

I would say that the idiomatic usage is: Get x [direct object] to [verb] with or without a direct object.

To here is a preposition after a noun. Some nouns take to: the solution to, the way to, the answer to, the trick to, the solution to, etc.

Cambridge Dictionary, to after a noun

"To as a preposition: after nouns A number of nouns are followed by to. These include nouns expressing direction or destination such as door, entrance, road, route, way:"

One could consider that the word trick is a "direction or destination". In any event, the noun trick "takes" to.

So the grammar here is two things:

• the [x] to [to follows certain nouns, it is a preposition
• getting x to y, a noun phrase or clause that means: making it so that there is some outcome.

Get x to y is the idiom.

On page x, some tricks to speed up your beauty routine is short-hand for: - On page x, [there are] some tricks to speed up your beauty routine.

That kind of shortening is allowed in certain types of advertorial-type writing. That said, it ain't great.

Obviously, that is the function usage of to signal a purpose.