VCE Methods Question Thread!

[TrueTears]

The only way I make it less intimidating is by referring to the formulas....

That's the correct way the concepts are heavily grounded in definitions in order to "test" them, you can't really use "intuition" to test it

[pi]

Use the formulaic definitions:
Indep: Pr(A int B) = Pr(A)*Pr(B)
Mut: Pr(A int B) = 0

[generalkorn12]

Thanks! It's re-assuring to know that they only seem less daunting through referring to formula.. phew :O

[BubbleWrapMan]

I should have a go at this question, I feel like my probability skills are slipping a little



(A and B are independent)

So

And hence

So I just realised now that if A and B are independent then so are A' and B, but that makes sense:







So if A and B are independent then (which is equivalent to saying the occurrence of B does not affect the probability of A; they are independent)

And hence

Hopefully this helps someone, but at the very least I learnt something xD

[duhherro]

Hey guys, just need help with a related rates question.


Sand is poured into a heap in the shape of a cone with angle 120 degrees at the vertex. If the height of heap is increasing at 3 cm per second when the height is 7 cm, then find the volume of the cone that is increasing?

DV/DT = DV/DH x Dh/dt, where Dh/Dt is 3?

[BubbleWrapMan]

The rest should be straightforward.

[Homer]

The simultaneous linear equation

kx - 3y= 0
5x - (k+2)y= 0

where k is a real constant, have a unique solution provided (Q1 2009 Exam 2). I always get stuck on these type of questions :s

[Bhootnike]

use matrices!

unique solution -it must have 1 solution  - when determinant does not equal 0.
so if you let det = 0:

so



then the values for k at which there is a unique solution would be k ∈ R \ {−5, 3}

[sin0001]

For integration questions in the tech-able exam, where you have to solve intregrals or find areas, do u show each step or can you just use your CAS to solve the integral?

[Hutchoo]

For integration questions in the tech-able exam, where you have to solve intregrals or find areas, do u show each step or can you just use your CAS to solve the integral?

For 1 mark: Write the answer.
For 2 or more marks: Write out the integral + show each step

[gubuchanchan]

Hey everyone,

I've been attempting trial exams the other day and in some questions involving powers, I usually leave the power negative
For example, writing 1/e^-2 -3e^-3

The answer they give is always positive, so in this case being e^2 -3/e^3

Is my answer fine or do we only get the mark if the power is positive, despite the answers meaning the same?

[Homer]

I don't think, they would! But I usually convert them into positives, its much easier to deal with

[Hutchoo]

It's usually easier to convert into positives for your own benefit. I always make mistakes with negatives!

[Mr. Study]

^ Love your DP Hutchoo.

Question: In MAV exams ... are we supposed to know fractional power graphs?

To be honest, I really don't want to have to rote learn them.

[BubbleWrapMan]

There's really only two categories of fractional power graphs: ones with a power less than one, and ones with a power greater than one. Those two kinds pretty much have the same shape, and whether they go to the negative side of the x-axis depends on whether the denominator of the power is even or odd.