VCE Methods Question Thread!

[helpmeplz]

So I'm having a total brain fade.........
How do I find the amplitude and period of a function?  I know for sin and cos its 2π / n but I'm at a loss to what I do after that?
f(x) = 4 sin ((x+π)/3)

Thanks!!

[keltingmeith]

So I'm having a total brain fade.........
How do I find the amplitude and period of a function?  I know for sin and cos its 2π / n but I'm at a loss to what I do after that?
f(x) = 4 sin ((x+π)/3)

Thanks!!

Amplitude is 4 - it's just the number out the front. (does not apply to combinations of circular functions)

Period is 2pi/n, where n is the number in front of the x. So, the period is 2pi/(1/3)=2pi * 3 = 6pi. (once again, does not apply to combinations of circular functions)

[Professor_Oak]

Does anyone know if VCAA still does real world rounding? i.e. one calculates 6.8 goats, but you round down to 6 as one cannot have .8 of a goat.

[keltingmeith]

Does anyone know if VCAA still does real world rounding? i.e. one calculates 6.8 goats, but you round down to 6 as one cannot have .8 of a goat.

AFAIK, yes. Granted, be careful, because it's okay to have an expected value in decimals, regardless of what you're measuring.

[GeniDoi]

Does anyone know if VCAA still does real world rounding? i.e. one calculates 6.8 goats, but you round down to 6 as one cannot have .8 of a goat.

Also for normal distribution questions you must include all values within the probability if it asks for the probability of being less than "x" even if the values are less than or equal to 0.

[LiquidPaperz]

for matrices if i have something like PA+B=C  and

i want P
i want A

how do i go about doing this? thanks

[faredcarsking123]

for matrices if i have something like PA+B=C  and

i want P
i want A

how do i go about doing this? thanks

PA = C-B
P = (C-B)A^(-1)

The A comes after (C-B) as it is after P
It must follow the same order

Therefore A = P^(-1)(C-B)

[Professor_Oak]

Also for normal distribution questions you must include all values within the probability if it asks for the probability of being less than "x" even if the values are less than or equal to 0.

What do you mean by this? Are you talking about significant figures?

[Valyria]

Hello,

If a question specifically says "x=/=2" and let's say we work out that the derivative is equal to 0 when x=1, 2, 3. Do we have to mention the 2 and then provide a short reason to why it's rejected? Or can we just omit it from the very first line of working?

[keltingmeith]

Hello,

If a question specifically says "x=/=2" and let's say we work out that the derivative is equal to 0 when x=1, 2, 3. Do we have to mention the 2 and then provide a short reason to why it's rejected? Or can we just omit it from the very first line of working?

I would write a quick little "but, x=/=2, so" and then restate the answers without the x=2. It takes an extra couple of seconds, but confirms both you know how it should be solved, but also why one answer is rejected.

[knightrider]

My school will be skipping this chapter.

What things are important for this chapter that i should do in my own time?

[keltingmeith]

My school will be skipping this chapter.

What things are important for this chapter that i should do in my own time?

None of them are truly important to 3/4.

Addition/multiplication principle - you can do if you really want, pretty straightforward.
Permutations - completely useless for VCE as we don't cover combinatorics, and this doesn't come up in distributions.
Factorials - comes up in calculating nCr, which you need for binomial distributions. Otherwise, not needed (particularly applications stuff)
Permutations using nPr - see previous.
Permutations involving restrictions - see previous.
Arrangements in a circle - legit don't know what this is referring to - so I'd say very skippable.
Combinations using nCr - you need to know how to compute nCr - you do not need to know about combinations.
Applications to Probability - this is the only exercise worth it in terms of what you need for 3/4. However, any applications involving strict combinatorics (i.e. hypergeometric distribution) are not covered in methods.

Your school is skipping this chapter because you REALLY don't need it. Schools that cover it are almost (almost, but not completely) wasting the time of their students in terms of what they need for 3/4.

[knightrider]

None of them are truly important to 3/4.

Addition/multiplication principle - you can do if you really want, pretty straightforward.
Permutations - completely useless for VCE as we don't cover combinatorics, and this doesn't come up in distributions.
Factorials - comes up in calculating nCr, which you need for binomial distributions. Otherwise, not needed (particularly applications stuff)
Permutations using nPr - see previous.
Permutations involving restrictions - see previous.
Arrangements in a circle - legit don't know what this is referring to - so I'd say very skippable.
Combinations using nCr - you need to know how to compute nCr - you do not need to know about combinations.
Applications to Probability - this is the only exercise worth it in terms of what you need for 3/4. However, any applications involving strict combinatorics (i.e. hypergeometric distribution) are not covered in methods.

Your school is skipping this chapter because you REALLY don't need it. Schools that cover it are almost (almost, but not completely) wasting the time of their students in terms of what they need for 3/4.

Thanks so much EulerFan101 

[knightrider]

My school will be skipping this chapter.

What things are important for this chapter that i should do in my own time?

Matrices 309
7A Addition and subtraction of
matrices 309
Exercise 7A 315
7B Multiplying matrices 316
Exercise 7B 318
7C Solving matrix equations 320
7D Matrices and transformations 325
Exercise 7D 328

My school is also skipping this exercise
Transition matrices and Markov chains-Is this important

[keltingmeith]

My school will be skipping this chapter.

What things are important for this chapter that i should do in my own time?

Matrices 309
7A Addition and subtraction of
matrices 309
Exercise 7A 315
7B Multiplying matrices 316
Exercise 7B 318
7C Solving matrix equations 320
7D Matrices and transformations 325
Exercise 7D 328

My school is also skipping this exercise
Transition matrices and Markov chains-Is this important

Methods does not explictly assess matrix arithmetic (7A and 7B), however knowledge of it is very useful for when you use matrices (transformations and markov chains). 7C shouldn't be required, but it's still handy to know (just in case). 7D would be a very important exercise.

Tl;dr, I'd do all of them, but 7C isn't that big a deal.

On Markov chains and transition matrices - your school is stupid to skip this (welp, maybe not, I don't know the teacher's/classes situation). Holy crap are these important (and difficult to understand for most). I would highly recommend going over them over the holidays.