are u allowed to use 4u techniques on a 2u paper? (2 Viewers)

[Trev]

We have had to do the past 2 mathematics papers, except we do not have to anymore

 

[FinalFantasy]

yea we got forced to do some 2unit things as well

 

[krabby_me]

Although it is possible to use 4u and 3u stuff in 2u exams. Its better if in class you practice all of the techniques, in case an exam asks to use a specific method.
For the safe side im going to use all my 2u techniques in the 2u exam and my 3u ones in 3u.

 

[dawso]

yeah, unless they say 2 use a specific technique, u can do it in any way u want, the most common one is integration, (in 3 unit) wen u will hav 2 integrate an inverse trig function, they expect you to it using the area of a square minus the definite integral of the appropriate trig function, however, its easier to do it by parts (a 4unit technique)

 

[FinalFantasy]

yeah, unless they say 2 use a specific technique, u can do it in any way u want, the most common one is integration, (in 3 unit) wen u will hav 2 integrate an inverse trig function, they expect you to it using the area of a square minus the definite integral of the appropriate trig function, however, its easier to do it by parts (a 4unit technique)

"u can do it in any way u want"
but on some other thread recently, think it's on the "Limits" thread, shafqat said u can only use 4u techniques on 3u, but u can't just use "any" way

 

[HayleeKate]

The BoS uses stuff outside the scope of the syllabus so I dont see why we cant.
For example, in ext 2, partial fractions, its in the syllabus that partial fraction questions with repeat factors in the denominator (I think thats it, or something like that in partial fractions, cant remember exactly which method/question) are outside the scope of the syllabus, yet they've been tested in HSC exams several times. MY teacher warned me about it, and its also in the textbook. So even though THATS not in the syllabus they put it in the exam, I say we can take methods which arent in the syllabus and put THEM in the exam if we bleedin' well want to.

 

[niall045]

If they don't state a technique to use and if the way you're doin it is legit then you're fine. Its all maths.

 

[Li0n]

It makes it much more fun if you use the normal methods ;P

 

[Estel]

Some of you are too idealistic.
Approach the exams with more cynicism or you'll learn to regret it...

 

[velox]

I agree, get the basics right first. No point in overcomplicating the exams.

 

[HayleeKate]

Well, still not positively sure whether you can or not, but, I just did. Just finsihed my 2u mid-course exam, and on one question (which I really thought I knew how to do), ended up with complex numbers in my working. I got the correct answer, tested it and it was correct, and the same as 2u friends who did it in the normal 2u way. I couldnt figure what the hell I did to get a bunch of i's, but I got rid of them and ended up with a good, reasonable answer. We'll have to wait and see how many marks I lose for using a 4u technique, but I'm pretty sure that will depend on which teacher marks my exam (lets hope its Craig or Gail, and NOT Kevin, or i'll end up with zero)

 

[FinalFantasy]

hmm what was da q.? do u remember?
and i would like to know if u got any marks for that too!

 

[Trev]

If your talking about factorising a polynomial or whatever, you do not factorise past real numbers in 2u and 3u, only factorise into unreal numbers in 4u! (If that's what you mean).

 

[dawso]

lol, yeah, i really intrigued as to what this question was and how u managed to get complex numbers into a 2unit question?

 

[Slidey]

It's pretty easy to get complex numbers in if it is a trig question.

 

[dawso]

ah yes steele, very true......expand cos sin(3@) for example....

sin (2@+@) =......

or 4unit expanding by binomial and de moivres and equating real and imaginary??

 

[Slidey]

But wait, there's more!

http://whyslopes.com/freeAccess/trigonometry_and_complex_numbers.html

 

[want2beSMART]

yeah why not?

though only if you get the correct answer

 

[HayleeKate]

I managed to get complex numbers into a 4u exam by using completely the wrong, strangest method on earth, the real question is how I managed to get the correct answer! (through doing it correctly, I know I did). I realize now what I did.

The question was something like this:
If the cost of making a certain trip in a vehicle is given by C=2V + 392/V, where, V= the average speed of the vehicle. Find the speed which will give the cheaps trip. Worth 3 marks out of a shitload (probably 100, cant remember)

Simple question, all you do is differentiate C, find the minimum point, SO....
I differentiated C, and got....... C'= 2 + 392 {my error lies here, differentiate first term, integrate the second.......SHIT, maybe I should join general now}
but, that doesnt let me find the minimum turning point, it just gives me a constant, wtf?
So, after decided I was correct and the exam must be wrong, decided to try make C=0 and solve for V.
2V^2=-392,
V^2=-196,
V=14i,
test V=14, C=56
V=13, C=56 + 2/13
V=15, C= 56 + 2/15
so, V=14, cheapest trip
COMPLETELY INCORRECT, BUT CORRECT ANSWER.
It was about 2 minutes after walking from the exam that I realized I integrated and messed up doing the correct, first method with C'. I'm so embarrassed about the stupidness of my mistake, but, did I invent a new way to solve the question, or is it just a fluke ended up with the right answer?
We'll have to wait see what my teachers get out of it. I'm devastated that I threw out the bit of paper with my C'=... attempt, so now they'll just think I didnt know how to do the question, when I really did, just screwed up. STAPLE ALL WORKING OUT EVEN IF ITS SCRAP TO THE EXAM, IT COULD HAVE MARKS, EVEN IF YOU THINK YOU'RE WRONG!!!! I learnt the hard way!

 

[7minute]

I may be wrong, but I'm sure I remember my maths teacher telling us that you can't use complex numbers in a 3 unit paper. For example, if you're solving an equation and end up with x = square root of something negative, you have to say that there are no solutions and not continue on using i's etc.