VCE Methods Question Thread!

[Conic]

When you went from to you ignored the 1 when dividing by . You should have



which just brings you back to where you started.

[cosine]

When you went from to you ignored the 1 when dividing by . You should have



which just brings you back to where you started.

I dont understand though, why is it that can be simplified to but not the example i posted. Is it because we are multiplying the two in this example, but the other one we were adding 1 and not multiplying? Thanks

[pi]

Is it because we are multiplying the two in this example, but the other one we were adding 1 and not multiplying? Thanks

Yes.

Try and think of it using really simple numbers to convince yourself (this used to help me):


I think these rules were explained in the earlier Maths Quests (like Maths Quest 7 or so) or other texts, so might be worth having a look back then to re-familiarise yourself!

[dankfrank420]

I've always wondered why this thread is so active compared to the Further thread when twice as many people do Further.

[Zues]

I've always wondered why this thread is so active compared to the Further thread when twice as many people do Further.

furthers crap, you're going to hate it next year

[aaziz17]

I've always wondered why this thread is so active compared to the Further thread when twice as many people do Further.

i think its because further is a lot easier compared to methods.

[dankfrank420]

furthers crap, you're going to hate it next year

Yeah I got so bored in my Further transition classes, teaching us matrix addition and multiplication. But my teacher is pretty eccentric and has a pure math degree, so hopefully he'll make classes a bit interesting. TBH I only chose it for a no-effort 5th subject. I wish I chose spesh though, but my school wouldn't allow it since I didn't take GMA.

[knightrider]

In Methods, you have 2x2 transition matrices. There is a neat way to work out what the matrix means:

You know, from the steady state matrix, that the vertical column entries must sum to 1. Thus, each column represents a given event occurring. Each row represents an event that may occur. The main diagonal elements represent the chance that an event will occur given it occurred before. I'll make this clearer with an example.

Suppose the chance a girl scores a basket from a free throw is 0.8 if she gets it from the previous throw, and the chance she misses the shot is 0.7 if she missed the previous shot. Let the event 'basket' be B and let the event 'no basket' be b
Now, the vertical columns of the transition matrix have entries that sum to 1. It makes logical sense, therefore, to assign the first vertical column to refer to the probabilities that the girl will score or miss her next free throw given that she has already scored.
Then, the second column should refer to the chance that she'll score or miss her next free throw given that she just missed.
Now, the top left corner should refer to the chance that she scored given that she already scored, which is 0.8. Putting all the other information together, my labelled transition matrix looks like this:

                    B already occurred            b already occurred
B                 0.8                                    0.3         
b                 0.2                                    0.7

See if you can make sense of what I did here. This is essentially what I did in year 9 to ensure I'd remember how the heck to set a transition matrix up (because I was terrible at this back then).

Thanks Lzxnl 
How do you go about learning things in methods in terms of conceptual understanding and getting solid ideas of things

[Zues]

Yeah I got so bored in my Further transition classes, teaching us matrix addition and multiplication. But my teacher is pretty eccentric and has a pure math degree, so hopefully he'll make classes a bit interesting. TBH I only chose it for a no-effort 5th subject. I wish I chose spesh though, but my school wouldn't allow it since I didn't take GMA.

haha i didnt do gma #danktrue

[cosine]

Guys please assist me if you please

This was in the methods exam this year:



I know we need to use the chain rule here, but why would this method be wrong:

f(x)

f(x) ( this is done by timing everything in the brackets by a power of 1/2)

Can someone please tell me why? Is it also because as I said before its a plus and not a times inside the brackets or in simpler terms, can we only square root everything inside the bracket if its only one expression? If so, why cant we take the square root of 2 expressions inside the bracket?

[Orb]

Guys please assist me if you please

This was in the methods exam this year:



I know we need to use the chain rule here, but why would this method be wrong:

f(x)

f(x) ( this is done by timing everything in the brackets by a power of 1/2)

Can someone please tell me why? Is it also because as I said before its a plus and not a times inside the brackets or in simpler terms, can we only square root everything inside the bracket if its only one expression? If so, why cant we take the square root of 2 expressions inside the bracket?

That doesn't work because of basic index laws.

You can't say that (a+b)^5 = a^5 + b^5

Your method is easily checkable by simply considering, if I square your end result, does it = x^2 + 3

[Zues]

Oo

[pi]

Not to be demeaning, but I strongly suggest you go back to basics and revise your yr7/8/9 algebraic if these sort of issues are troubling you. This stuff is the bread and butter of what's expected knowledge and it's best to have the very fundamentals nailed down now before moving onto topics in calculus!

[keltingmeith]

I've always wondered why this thread is so active compared to the Further thread when twice as many people do Further.

Honestly, it's probably because AN is aimed at high achievers, and you'll see more high achievers doing methods than you'll find them doing further. Namely because these are the kind of people who were switched on in early high school, and are in a position to do methods. (in fact, to memory 2/12 of the 90+s in my school didn't do methods.) However, we still have plenty of help going towards the further threads if anybody does come on who wants help with further.

How do you go about learning things in methods in terms of conceptual understanding and getting solid ideas of things

Don't just spam questions, and don't just rote-learn formula and constantly apply them until you think you know what you're doing. Learn why things work. Why does a graph go up when the derivative is positive? Why can't we do (a+b)^2=a^2+b^2? Why does b^0=1 (for b=/=0)?

All maths classes are assumed to be learning a bunch of formula and knowing where to apply them - it's not. Mathematics is a beautiful language, and takings a maths subject should be seen as doing a LOTE. Sure, you COULD get by and do averagely by learning a bunch of different words (formula), but you're more likely to do well if you actually learned appropriate grammar and sentence structures (why things work and such).

[lzxnl]

Yep. EulerFan speaks the truth about how to learn maths. Understand what every frigging symbol means in every formula. Understand the placement of the symbols in the formula. Understand where formulas come from. Understand what every formula means.

If you can do the above 4, you'll do so much better than the ordinary guy who rote learns the course. When I did Methods and Spesh, I wasn't happy with my progress until I could pick out exactly what I did to get questions right and why my working was right.