[adamcrow64]

I like to know that candidates can recall their study. For engineers, one of the biggest mathematical learnings in their degree is the study and use of imaginary numbers. In Australia this is taught in year 11/12 and is taught to kids who show aptitude towards STEM. Identifying these early adopters has worked well for us. So the go to question that we use a lot is "What is the square root of minus one?".

This culls a lot of non mathematical people. (And we find that Mathematical people generally make for better STEM employees in a tech setting).

If they answer correctly (and many who get through the initial resume culling process do) then we follow up with a second question that is not important to answer but will show a candidates sense of curiousity (super important).

What is the answer to the first question to the power of the answer to the first question?

Fascinating answer to this second question that can delight the candidates we are after.

[cameronh90]

Do you work in a particularly mathematical field?

I've been working in tech for 15 years now, and can't remember any time that I've needed to use imaginary numbers. The only reason I still remember anything about them is because my hobby is electronics.

[anyfoo]

I have to agree. I love imaginary numbers, the complex exponential, both the s-plane and the z-plane. Because, like yours, my hobby is electronics.

Neither as a low level system programmer, nor in any of my high level programming jobs a long long time ago, have I ever needed imaginary numbers. Privately yes, but that's just when writing code for my hobby.

[olivermuty]

I ise imaginary numbers every day as a developer!

«Yes thats a quick 15 minute fix»

That number 15 turns out to be very imaginary most of the time :(

[jackblemming]

You might want to phrase it as the square root of negative one in the future.

[osrec]

Why?

[RhysU]

Because "minus" is the boolean subtraction operator not the unary negation operator despite a lot of colloquial misuse by native speakers.

The distinction is useful when reading aloud expressions like 3-(-2) as "three minus negative two".

[osrec]

Perhaps, but "negative one" would sound a little odd to lot of people from certain countries, including the UK, where "minus one" is the standard way of referring to a negative number. We would be perfectly okay with hearing "three minus minus two" in mathematical context.

[RhysU]

Americans would be OK hearing that too. It's just a more complicated grammar to parse.

Curiosity: How do you call the terminals on a battery?

[osrec]

Positive and negative for battery terminals.

But "minus five degrees" for temperature ;)