This seems like a pretty ineffective way to try to determine if someone is using CM's.

I am fairly good at math.  I use algebra, geometry, and trigonometry regularly in the course of my job.

I would certainly have a different reaction to a standard math equation than someone who hasn't done any math more complicated than balancing their checkbook for the past ten or fifteen years.

If I planned on using CM's, I would certainly be thinking of more difficult and consuming equations in my head during the polygraph test.  My mental activity during the "CM-detection equation" prior to the test would certainly be less than my mental activity as I distracted myself with mental trig problems during the test.

This seems to be just another subjective guesstimate to pile on top of the other guesstimates that comprise the entire polygraph process.

It would be funny if there were not such real consequences attached to the continued use of the polygraph.

day2day,

The polygraph community is playing with itself if it thinks it can reliably detect properly applied mental (mathematical and other) countermeasures.  There is Way too much variation in what they (the polygraph community) considers/accepts to be scoring criteria for normal (not artificially produced) significant responses.  

I presume they know this and what you have shared with us is just one more psychological ploy on the part of the utilizing examiner to let the examinee know that they are aware of the possibility of countermeasure usage and to scare the latter from employing a potentially useful tool.  Again, such nonsense has absolutely nothing to do with detecting countermeasures and in fact may lead the naive but would-be countermeasure user to a useful tool.  

Remember a control question has a beginning, a middle, and an end lasting on average 5 seconds (e.g., Prior to the age of 18, did you ever steal something from someone who trusted you?).  One who varies the initiation of the countermeasure along this time line and uses a sufficiently challenging question (e.g., sq rt of 2 times pi raised to the third power = ) will over the course of the many control questions posed during an exam likely be successful in his/her efforts.   One might ask what a sufficiently challenging problem is.  As the good sergeant has pointed out this will vary among examinees.   A sufficiently challenging question/problem is defined simply as one that you do not know the answer to in advance (in general made up on the fly so to speak) and not likely (would be highly challenged) to compute in the seconds following application of the countermeasure.  It should be pointed out for those who might seek to apply such mental countermeasures, that an overall successful countermeasure effort will likely include other countermeasures as well.  It should also be pointed out that successful performance might be made more likely with a small amount of advance practice while monitoring (gaining feedback from) the output from one or more channels of the common polygraph.

If anyone of stature within the polygraph community believes the aforementioned not to be the case, please advise when we might witness and challenge/critique your demonstration of purported reliable countermeasure detection.  For those of you in (and/or who serve) the polygraph community and who schedule seminars and receive funding for teaching and awarding continuing education credits on subjects such as this, I accept your thanks in advance.  lol