VCE Methods Question Thread!

[ras]

Last year in my bound notes I dedicated a page to my most common silly mistakes. I had a checklist of things I had to check through each question if I had enough time. It was mainly things such as units, checking working, what form of answer does the question ask for. A key point, if you have the time, is not moving on to the next question until you have reread the question you have just finished. Keep on trying to minimise silly mistakes. It may seem like you're not getting anywhere but at some point soon it should all come together

[silverpixeli]

Are there any tips for preventing silly mistakes? This has probably been asked before, but the amount I make is disastrous, like the 2012 vcaa Ex 1, I lost 7 marks to silly mistakes.

Last year in my bound notes I dedicated a page to my most common silly mistakes. I had a checklist of things I had to check through each question if I had enough time. It was mainly things such as units, checking working, what form of answer does the question ask for. A key point, if you have the time, is not moving on to the next question until you have reread the question you have just finished. Keep on trying to minimise silly mistakes. It may seem like you're not getting anywhere but at some point soon it should all come together

good ideas!
re-reading the question and stuff is always my best tip for reducing silly mistakes
if you have time, you can often try to solve the question a different way, or backwards, 'testing' your answer to see if it came out right
in some questions, you can just use common sense to tell if an answer is horribly wrong or not based on the context (like, a 1000m tall building is possible but suspicious)
also, go over your exam after you finish if you still have time on the clock and look for things you missed! i lost a mark in specialist last year for forgetting to write the range in a question that asked for domain and range, one of the easiest marks on the paper

[TrebleClef]

Last year in my bound notes I dedicated a page to my most common silly mistakes. I had a checklist of things I had to check through each question if I had enough time. It was mainly things such as units, checking working, what form of answer does the question ask for. A key point, if you have the time, is not moving on to the next question until you have reread the question you have just finished. Keep on trying to minimise silly mistakes. It may seem like you're not getting anywhere but at some point soon it should all come together

good ideas!
re-reading the question and stuff is always my best tip for reducing silly mistakes
if you have time, you can often try to solve the question a different way, or backwards, 'testing' your answer to see if it came out right
in some questions, you can just use common sense to tell if an answer is horribly wrong or not based on the context (like, a 1000m tall building is possible but suspicious)
also, go over your exam after you finish if you still have time on the clock and look for things you missed! i lost a mark in specialist last year for forgetting to write the range in a question that asked for domain and range, one of the easiest marks on the paper

Thank you!

[keltingmeith]

also, go over your exam after you finish if you still have time on the clock and look for things you missed! i lost a mark in specialist last year for forgetting to write the range in a question that asked for domain and range, one of the easiest marks on the paper

I have a friend who lost 3-5 marks on that exam 1 because he completely forgot to answer a question, which really sucks considering how easy the paper was and (resultedly) how high you needed to score for that A+.

So, if you have finished and have time at the end, make sure you answered everything first.

[Valyria]

Hey,

Could someone please explain why we can't use r/2=h/5 to determine h in terms of r?

[keltingmeith]

Hey,

Could someone please explain why we can't use r/2=h/5 to determine h in terms of r?

Can you explain how your two triangles are similar, because I don't think they are.

[Valyria]

Can you explain how your two triangles are similar, because I don't think they are.

I initially thought the right-angled triangle inscribed in the cylinder was similar to the right-angled triangle of the cone because they had equal angles with corresponding sides of equal ratio but that's obviously not the case

[keltingmeith]

I initially thought the right-angled triangle inscribed in the cylinder was similar to the right-angled triangle of the cone because they had equal angles with corresponding sides of equal ratio but that's obviously not the case

My rule of thumb:
Only consider two triangles as similar if two angles are the same. Working with ratios is just asking for trouble.

The triangles you described both have a right angle. Do they have another angle the same? Do you have proof of this? Can you see any other triangles?

[Valyria]

My rule of thumb:
Only consider two triangles as similar if two angles are the same. Working with ratios is just asking for trouble.

The triangles you described both have a right angle. Do they have another angle the same? Do you have proof of this? Can you see any other triangles?

Ah, they only have a right angle that is common. Instead of the triangle inscribed in the cylinder,could the triangle that uses the height of the cylinder, side with length (r-2) and hypotenuse that is along the cone's slanted edge be used?

[keltingmeith]

Ah, they only have a right angle that is common. Instead of the triangle inscribed in the cylinder,could the triangle that uses the height of the cylinder, side with length (r-2) and hypotenuse that is along the cone's slanted edge be used?

I'm sure my ambiguous answering of this is pissing you off, but this close to exams I feel it would be better off for you to get the answer with as little help as possible.

You can use that triangle, but why?

[Valyria]

I'm sure my ambiguous answering of this is pissing you off, but this close to exams I feel it would be better off for you to get the answer with as little help as possible.

You can use that triangle, but why?

Haha, nah I appreciate the walk through. Well they share a right-angled triangle and the angle subtended by the slanted edge of the cone and its base. Thus, as 2 angles are equal, they are similar triangles

[keltingmeith]

Haha, nah I appreciate the walk through. Well they share a right-angled triangle and the angle subtended by the slanted edge of the cone and its base. Thus, as 2 angles are equal, they are similar triangles

Logic seems pretty reasonable to me, I reckon you've got the concept down.

Food for thought: we actually say triangles are similar because if three angles are the same, then the sides can be taken in the same ratio. This is why it's best to take two angles to be the same - if two angles are the same, then the third angle HAS to be the same (geometry laws), which allows us to use the ratio property. If we already know the ratio is fine, then we wouldn't be able to use the ratio property in this question - because we'd already know h and r to begin with.

[althepal]

Hi everyone sorry if this has already been asked but can someone explain to me why in vcaa exam 2 2011 q.4f dt/dx is less than or equal to 0? I thought to find a minimum it would just be dt/dx = 0 only not less than. Thank you!

[Champ101]

Quick question: Is the maximum/minimum value of an absolute equation (e.g. abs((2x-1)^2 + 3) ) just the derivative of the inside equal to zero, or, do you have make the derivative of the absolute equal to zero?

[Zealous]

Quick question: Is the maximum/minimum value of an absolute equation (e.g. abs((2x-1)^2 + 3) ) just the derivative of the inside equal to zero, or, do you have make the derivative of the absolute equal to zero?

Well, is always positive, so putting it inside of a modulus (absolute) will make no difference. So yes you can take the derivative and let it equal 0.

For more complex cases, doing a sketch of a graph or splitting the modulus into a hybrid function over multiple domains can always help.