Re: HSC 2016 MX2 Combinatorics Marathon
Ok, I'm certain my above answer is wrong. Anyway, I have time now so I might as well write a larger response to the whole question:
i) P(k)(nCk) is saying choose k letters, then arrange them in all the ways that they can form a word. So summing this from...
Yeah I just showed that the discriminant was equal to zero, and hence that was a double root of the derivative, and thus as it is also a root of the function, it must be a triple root.
For 12 d ii), I just subbed in y = c^2/x and rearranged to get a quadratic, then used the product of roots. 13 will take too long to type out, but just set T2 greater than T1 and solve for w.
I don't really think it was easier, around the same difficulty. I don't know the general consensus though, my cohort is too small to get a good idea of that.
Yeah honestly. Some of the marks were just way too easy to obtain, especially in the last question, seeing as though that question should be very difficult. And then there was that ellipse question. I don't know how that was worth 4%.
EDIT: Yeah just skimmed it again, I forgot how much they...
Well, out of my cohort of 7, the consensus was that the whole paper was easy. I didn't really think the algebra was too tedious honestly, maybe a couple questions here and there, but overall it wasn't that bad. A lot of people seemed to skip 16 though.