Edexcel Decision MathematicsWatch
I personally hated D1 because it seemed to be very loosely linked with maths indeed. I also do P1 and S1 which I thought were reasonable enough. However the D1 test was very difficult because you have LOTS of work to do in just 90 minutes. I think that of the three modules, I did very poorly on D1. However you should not let that put you off too much because I am AWFUL at exams so maybe its just me.....
At first I liked the way the algorithms were somewhat useful in the real world, (and so not much like pure maths). But after a while, too many of the algorithms become mindless acts in arithmatic on numbers in a table.
The exams are reasonably easy, though saying that, this years D2 was a bit Iffy..
I don't think u can do Decision maths as a complete AS - Level on it's own, unless there's a third module out there ...
As a result, you end up using some fairly involved algorithms to solve very minor problems which contain little data, few variables, and few decisions. The best example of this is probably the D2 Dynamic Programming, where the problems are so limited that you could often just write the solution by inspection.
Having said all this, some of it is quite interesting.