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September 10, 2025, 07:57:30 am

Author Topic: Mathematics Question Thread  (Read 1626435 times)  Share 

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Aaron12038488

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Re: Mathematics Question Thread
« Reply #2745 on: October 10, 2017, 06:39:05 pm »
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i have my first 2 unit test in week 7 i believe...
how many weeks will it take for the topic Series and Sequences AND geomterical applications of calculus?

Savas_P

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Re: Mathematics Question Thread
« Reply #2746 on: October 10, 2017, 06:56:11 pm »
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i have my first 2 unit test in week 7 i believe...
how many weeks will it take for the topic Series and Sequences AND geomterical applications of calculus?

lol at school it took a few weeks for each topic, you could probably cover at home in a few hours. I wouldn't stress too much.

RuiAce

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Re: Mathematics Question Thread
« Reply #2747 on: October 10, 2017, 07:42:51 pm »
+4

The working out for 10 is weird could someone also tell me what their answer was with working out?
Sorry for the spam thanks so much in advance guys


Nothing looks overly confusing here. Please mention which line you feel uncomfortable with.
i have my first 2 unit test in week 7 i believe...
how many weeks will it take for the topic Series and Sequences AND geomterical applications of calculus?
Depends for school to school. Probably a fair call in your concern in that those are two of the three largest topics, but it isn't an impossibility.

Usually, if your school messes up with the schedule, they will work their way around it, possibly changing their mind and only examine half of one of the topics. They are (as alluded to above) "learn-able" in a few hours (spread over probably two or three days though), but your school will deal with things as they come if anything.

nattynatman

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Re: Mathematics Question Thread
« Reply #2748 on: October 11, 2017, 10:24:07 am »
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Helloo I have a question regarding more so how to think about questions/apply your knowledge/formulas:
Usually I struggle during practice questions and doubt my answer because it looks so absurd. I feel like it's easy to second guess myself in maths. This has been the downfall of my marks (average 60%) and once I check the solutions it all makes sense - but I still can't seem to apply it in the process of finding the answers. D:
What are some ways I can fix this before my 2u exam? (I've been doing past papers too)
Thanks!!

RuiAce

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Re: Mathematics Question Thread
« Reply #2749 on: October 11, 2017, 11:33:33 am »
+3
Helloo I have a question regarding more so how to think about questions/apply your knowledge/formulas:
Usually I struggle during practice questions and doubt my answer because it looks so absurd. I feel like it's easy to second guess myself in maths. This has been the downfall of my marks (average 60%) and once I check the solutions it all makes sense - but I still can't seem to apply it in the process of finding the answers. D:
What are some ways I can fix this before my 2u exam? (I've been doing past papers too)
Thanks!!

Second guessing can be quite normal, and sometimes put you back on track. When you should act on it, however, is usually not when you actually start doubting it. Unless you're fully confident that you know the correct method, you should leave that question for now and complete what's left on the paper, because it's all about mark maximisation. Keep on trying and attempting all the remaining questions, and then once you feel as though you can't do any more (paper too hard by then, time etc.) go back to what the question you were concerned about.

It's easy to look at a question and realise "how" it's done, but it can be far more difficult understanding WHY that approach was taken. When you first started doing past papers, this was not problematic, as you didn't need to develop any sense on intuition on what method to use. Now that you have done a fair few, you need to consider why. Instead of "how is this question done?", be more focused on "how was this one of the many correct approaches, if not the only correct approach to tackling it?". Also, remember that there can be multiple ways of doing the same question.

Because the questions themselves tend to differ but involve the exact same methods/formulae/techniques, look out for any key characteristics as well. E.g. in geometry, use all key details but also try to "see" the theorem. With quadratics, the discriminant can appear at some really weird places. If you need guidance on this, provide further examples of questions with their solutions and explain where the confusion lies.

gilliesb18

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Re: Mathematics Question Thread
« Reply #2750 on: October 11, 2017, 12:07:23 pm »
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Hello,
I just need help on a locus question. I am new to the topic so I need heaps of help!!!
Question: Find the equation of the locus of point P(x,y) that moves so that it is equidistant from the points (3,2) and (-1,5).
I started to work out the line perpendicular to the line joining the two points. Is that right? Cause I then looked at the answers and I was completly wrong... At least it looked that way!

Thanks heaps in advance....

Shadowxo

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Re: Mathematics Question Thread
« Reply #2751 on: October 11, 2017, 12:22:51 pm »
+2
Hello,
I just need help on a locus question. I am new to the topic so I need heaps of help!!!
Question: Find the equation of the locus of point P(x,y) that moves so that it is equidistant from the points (3,2) and (-1,5).
I started to work out the line perpendicular to the line joining the two points. Is that right? Cause I then looked at the answers and I was completly wrong... At least it looked that way!

Thanks heaps in advance....
Drawing it can help you visualise it better
So this results in a line that is perpendicular to the line joining them (find the gradient of the line joining them and use m1*m2= -1 to find the gradient of the normal / perpendicular line) and passes through the midpoint
I suggest using y-y1=m(x-x1) to find the equation, with (x1,y1) being the midpoint
Post your working if you're still stuck :) Good luck!
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Natasha.97

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Re: Mathematics Question Thread
« Reply #2752 on: October 11, 2017, 12:29:20 pm »
+3
Hello,
I just need help on a locus question. I am new to the topic so I need heaps of help!!!
Question: Find the equation of the locus of point P(x,y) that moves so that it is equidistant from the points (3,2) and (-1,5).
I started to work out the line perpendicular to the line joining the two points. Is that right? Cause I then looked at the answers and I was completly wrong... At least it looked that way!

Thanks heaps in advance....

Hi!

Agree with Shadowxo in terms of drawing it out :)

An alternative method would be getting an arbitrary point on the line e.g. P = (x, y), use the distance formula to get PA and PB, then apply the condition in the question (equidistant: PA = PB) to solve :)

Edit: Added solution in case you're stuck :)

« Last Edit: October 11, 2017, 04:06:27 pm by Jess1113 »
Life is weird and crazy as heck but what can you do?

RuiAce

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Mathematics Question Thread
« Reply #2753 on: October 11, 2017, 12:38:02 pm »
+2
Drawing it can help you visualise it better
So this results in a line that is perpendicular to the line joining them (find the gradient of the line joining them and use m1*m2= -1 to find the gradient of the normal / perpendicular line) and passes through the midpoint
I suggest using y-y1=m(x-x1) to find the equation, with (x1,y1) being the midpoint
Post your working if you're still stuck :) Good luck!
This approach is perfectly valid (and I don’t think you can be marked wrong for it), but in the HSC the one they teach is Jess’s version. An arbitrary point P(x,y) is made to satisfy the equation PA=PB, and then distance formulae are applied. It’s usually the recommended approach because it relaxes the need to assume the shape of the locus (I.e. a line), which is only really expected in 4u

(I don’t have enough time right now to actually write up the solution using that method right now)

kiiaaa

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Re: Mathematics Question Thread
« Reply #2754 on: October 11, 2017, 09:19:29 pm »
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Hi guys
I'm struggling with all of question b and when I looked at the answer i got even more confused on how they did it.lol Could you please explain to me how to solve this please? as like I found the answers sort of vague so i don't know what they did exactly and why
it is q14 from the 2013 hsc paper incase you are wondering
Thank you very much! :))

RuiAce

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Re: Mathematics Question Thread
« Reply #2755 on: October 11, 2017, 09:39:06 pm »
+3
Hi guys
I'm struggling with all of question b and when I looked at the answer i got even more confused on how they did it.lol Could you please explain to me how to solve this please? as like I found the answers sort of vague so i don't know what they did exactly and why
it is q14 from the 2013 hsc paper incase you are wondering
Thank you very much! :))

because distance = speed*time and we have speed=80, time=t.


______________________________


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But part ii) is just your average max/min problem. Please expand on the problem regarding that part.

gilliesb18

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Re: Mathematics Question Thread
« Reply #2756 on: October 12, 2017, 09:41:48 am »
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This approach is perfectly valid (and I don’t think you can be marked wrong for it), but in the HSC the one they teach is Jess’s version. An arbitrary point P(x,y) is made to satisfy the equation PA=PB, and then distance formulae are applied. It’s usually the recommended approach because it relaxes the need to assume the shape of the locus (I.e. a line), which is only really expected in 4u

(I don’t have enough time right now to actually write up the solution using that method right now)
Thanks heaps!! I will work on that then...

sidzeman

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Re: Mathematics Question Thread
« Reply #2757 on: October 12, 2017, 11:32:21 am »
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The first one was already addressed (and will potentially be added to the compilation)

You should either copy out the diagram and annotate this, or print off the diagram and then annotate it. You should also annotate further knowing that you now have a pair of congruent triangles, therefore all sides on the triangle are equal.


To what extent was it obvious - I do not know. But the diagram really looked suspicious - the three congruent triangles were just staring at me after I looked hard enough.

_______________________

Label some more information on your diagram.



Sorry, I'm still failing to understand what you did for the similar triangle question. I was able to prove congruency for all 3 triangles. I then calculated angle YCM using the angle sum of a triangle (as angle MYC must be 60). However I get lost up to that point - when you say using trig and find those ratios, what exactly are you doing? Sin rule??

RuiAce

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Re: Mathematics Question Thread
« Reply #2758 on: October 12, 2017, 11:40:07 am »
+1
Sorry, I'm still failing to understand what you did for the similar triangle question. I was able to prove congruency for all 3 triangles. I then calculated angle YCM using the angle sum of a triangle (as angle MYC must be 60). However I get lost up to that point - when you say using trig and find those ratios, what exactly are you doing? Sin rule??
Right angled trigonometry. Always be on the look-out for right-angled triangles, because that allows you to use the very fundamental formulae.

sidzeman

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Re: Mathematics Question Thread
« Reply #2759 on: October 12, 2017, 11:52:55 am »
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Right angled trigonometry. Always be on the look-out for right-angled triangles, because that allows you to use the very fundamental formulae.

Hmmm, for your 2nd trig use then (tan(angle YCM)) - is it not meant to be MY over MC? How did you get AC instead?