help for harder 3u

[3.14159265359]

hello!

harder 3u is where I mostly lose my marks. ughhhh ESPECIALLY the combinations question. I usually skip them because I have zerooooo idea what to do. I'm fine with everything else its just harder 3u (mainly circle geo, sometimes inequalities and COMBINATION/PROBABILITY). when I did my 2u hsc last year, 2u probability was a breezeeeeeee but then comes 3u probability I'm screwed. any help on how to improve.

thank you

[RuiAce]

(3U (+ harder 3U for the 4U course) probability isn't founded on basic intuition. It's entirely combinatorial. It all relies on \( P(\text{Event}) = \frac{\text{No. of favourable outcomes}}{\text{Total outcomes}}\).)

But yeah, perms and combs are probably the hardest thing in 4U and ultimately you're never alone with it. I wasn't good at it in high school either.

In my lecture, I've stated techniques on how combinatorics problems can be approached. You should review them and see if there's any techniques you can get out of it. There's an example to go with each technique to suggest how it can be used, and the techniques do cover quite a fair lot of possibilities. But of course they might not cover every possibility (because you never know what they would throw with perms and combs) so definitely raise any that you don't feel are covered.

(A few extra tips were mentioned in my MX2 notes, but if you don't have a copy of that I obviously wouldn't push for it days before the exam.)

Also, it does require some common sense and some intuition. Break the problems down, and compare them to problems you've done in the past, but don't be scared to put some common sense into it.

With circle geometry, the theorems are obviously the same as in 3U. The jump to 4U however typically involves a) more of a need to construct lines by yourself, and b) things becoming less obvious (e.g. use of the word 'similarly', use of similar triangles etc.). Remember for inequalities you can always work backwards on the side to help out

[3.14159265359]

(3U (+ harder 3U for the 4U course) probability isn't founded on basic intuition. It's entirely combinatorial. It all relies on \( P(\text{Event}) = \frac{\text{No. of favourable outcomes}}{\text{Total outcomes}}\).)

But yeah, perms and combs are probably the hardest thing in 4U and ultimately you're never alone with it. I wasn't good at it in high school either.

In my lecture, I've stated techniques on how combinatorics problems can be approached. You should review them and see if there's any techniques you can get out of it. There's an example to go with each technique to suggest how it can be used, and the techniques do cover quite a fair lot of possibilities. But of course they might not cover every possibility (because you never know what they would throw with perms and combs) so definitely raise any that you don't feel are covered.

(A few extra tips were mentioned in my MX2 notes, but if you don't have a copy of that I obviously wouldn't push for it days before the exam.)

Also, it does require some common sense and some intuition. Break the problems down, and compare them to problems you've done in the past, but don't be scared to put some common sense into it.

With circle geometry, the theorems are obviously the same as in 3U. The jump to 4U however typically involves a) more of a need to construct lines by yourself, and b) things becoming less obvious (e.g. use of the word 'similarly', use of similar triangles etc.). Remember for inequalities you can always work backwards on the side to help out

when you say "compare them to problem you've done in the past" the problem with that Is, for perms and combs I always forget how I do a question. so if I do a question and see a similar question couple weeks later ill forget what the hell I did.

and the combinatorics problems, for the past couple years the last q of the paper is that type of question and they are all different and its so hard to do  so if the last q this year is a probability q/those ugly complex I am screweddddddddd

[RuiAce]

when you say "compare them to problem you've done in the past" the problem with that Is, for perms and combs I always forget how I do a question. so if I do a question and see a similar question couple weeks later ill forget what the hell I did.

and the combinatorics problems, for the past couple years the last q of the paper is that type of question and they are all different and its so hard to do  so if the last q this year is a probability q/those ugly complex I am screweddddddddd

In that case, it's time to focus. Put a pause to the concepts that you're more confident with, and keep locating questions under the combinatorics topics. Of course you don't want to be doing this constantly, but you should spend either one full day, or if you time it well then two half days targeting this specific area of weakness and doing what you can about it. You can choose to do a full past paper as well, but just for a very temporary period attempt to prioritise these.

(Emphasis on temporary, of course, given how close the exam is)

[3.14159265359]

In that case, it's time to focus. Put a pause to the concepts that you're more confident with, and keep locating questions under the combinatorics topics. Of course you don't want to be doing this constantly, but you should spend either one full day, or if you time it well then two half days targeting this specific area of weakness and doing what you can about it. You can choose to do a full past paper as well, but just for a very temporary period attempt to prioritise these.

(Emphasis on temporary, of course, given how close the exam is)

thank you!!! I'm trying to manage math and bio but haha not going so well

[RuiAce]

thank you!!! I'm trying to manage math and bio but haha not going so well

Pretty much yeah, especially since NESA always loves putting bio and math so close together this is always a bit of a struggle. And you also gotta add appropriate breaks into your study schedule. Those times given were more or less rules of thumb - ultimately all that really matters is that you put some more reasonable focus into those topics you're struggling at. It's up to you how much you wanna put in

[3.14159265359]

Pretty much yeah, especially since NESA always loves putting bio and math so close together this is always a bit of a struggle. And you also gotta add appropriate breaks into your study schedule. Those times given were more or less rules of thumb - ultimately all that really matters is that you put some more reasonable focus into those topics you're struggling at. It's up to you how much you wanna put in

yes screw nesa for having math after bio (the 2 most popular subjects)  😤😤😤

thank you again for your help!!