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March 29, 2024, 05:33:55 am

Author Topic: Mathematics Question Thread  (Read 1296829 times)  Share 

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RuiAce

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Re: Mathematics Question Thread
« Reply #690 on: October 20, 2016, 06:09:10 pm »
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Thank You so muchh! Much more easier to understand :D
Quick question... Why does root 2 go infront and root 1 becomes negative?



nibblez16

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Re: Mathematics Question Thread
« Reply #691 on: October 20, 2016, 06:13:41 pm »
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nibblez16

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Re: Mathematics Question Thread
« Reply #692 on: October 20, 2016, 06:43:46 pm »
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Can you please help me with the last question

jakesilove

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Re: Mathematics Question Thread
« Reply #693 on: October 20, 2016, 06:49:26 pm »
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Can you please help me with the last question

Hey! So we can say that Alex's salary grows like this



If they save a third of their funds, then they will save




etc. Now, we want this value to equal $87,500. You can use the sum of an arithmetic sequence (a formula you should definitely know!) to simplify the terms in brackets. Then, set that equal to 87,500 and solve for n! Let me know if you need a worked solution for this.

Jake
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yasmineturner

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Re: Mathematics Question Thread
« Reply #694 on: October 20, 2016, 06:54:17 pm »
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Hi everyone,
I was just wondering if anyone could help me with this question: 10b from the 1995 10b (i, ii, iii, iv).
Thanks for your help :)

RuiAce

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Re: Mathematics Question Thread
« Reply #695 on: October 20, 2016, 06:56:46 pm »
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Hi everyone,
I was just wondering if anyone could help me with this question: 10b from the 1995 10b (i, ii, iii, iv).
Thanks for your help :)
Refer to post #522

jakesilove

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Re: Mathematics Question Thread
« Reply #696 on: October 20, 2016, 06:57:41 pm »
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Hi everyone,
I was just wondering if anyone could help me with this question: 10b from the 1995 10b (i, ii, iii, iv).
Thanks for your help :)

Hey! Welcome to the forums! You can find velocity by differentiating displacement, so




To show that there are only two times where these velocities are the same, I would graph the two functions. There will only be two intercepts, thus showing that there are only two times in which the particles have the same velocity!


Annnnd I'm going to stop answering, because Rui is finding a solution he already wrote up. Bear with us! Good luck tomorrow :)
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nibblez16

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Re: Mathematics Question Thread
« Reply #697 on: October 20, 2016, 07:01:17 pm »
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Hey! So we can say that Alex's salary grows like this



If they save a third of their funds, then they will save




etc. Now, we want this value to equal $87,500. You can use the sum of an arithmetic sequence (a formula you should definitely know!) to simplify the terms in brackets. Then, set that equal to 87,500 and solve for n! Let me know if you need a worked solution for this.

Jake

Okay understandable! But what do we do with the 1/3? Thats where I am confused, how do we place it into formula?

jakesilove

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Re: Mathematics Question Thread
« Reply #698 on: October 20, 2016, 07:11:09 pm »
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Okay understandable! But what do we do with the 1/3? Thats where I am confused, how do we place it into formula?

We'll end up getting something that looks like



Where we know d, and we know a. Therefore, it should be fairly straight-forward to solve for n!
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yasmineturner

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Re: Mathematics Question Thread
« Reply #699 on: October 20, 2016, 07:43:54 pm »
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Hi again,
I was just wondering if any could help as I am unsure of how to complete question 10a, iv of the 2010 paper. I have attached a copy of the question and my working for the other parts :) Thankyou

RuiAce

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Re: Mathematics Question Thread
« Reply #700 on: October 20, 2016, 07:45:54 pm »
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Hi again,
I was just wondering if any could help as I am unsure of how to complete question 10a, iv of the 2010 paper. I have attached a copy of the question and my working for the other parts :) Thankyou
Both ∆ABC and ∆ACD are isosceles.

This implies that we can use base angles on isosceles triangles twice.

< ACD = < ABC (= common < A)

yasmineturner

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Re: Mathematics Question Thread
« Reply #701 on: October 20, 2016, 07:48:32 pm »
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Both ∆ABC and ∆ACD are isosceles.

This implies that we can use base angles on isosceles triangles twice.

< ACD = < ABC (= common < A)
How do you do part iv? Thankyou :)

jakesilove

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Re: Mathematics Question Thread
« Reply #702 on: October 20, 2016, 07:52:08 pm »
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Hi again,
I was just wondering if any could help as I am unsure of how to complete question 10a, iv of the 2010 paper. I have attached a copy of the question and my working for the other parts :) Thankyou


Hey! Firstly, note that y must be positive. We know that cos(theta) can be between -1 and 1, so actually, the maximum value of 2cos(theta) is 2. However, (1-2cos(theta))=1-2=-1 is negative, which is not allowed for the size of a line. If you let cos(theta)=-1, you get 2cos(theta)=-2. So, the maximum value is a(1-2cos(theta))=a(1-2(-1))=3a. y will always have to be less than that!

This was really badly explained. Hope it made sense!
ATAR: 99.80

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RuiAce

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Re: Mathematics Question Thread
« Reply #703 on: October 20, 2016, 07:53:11 pm »
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Oh apologies on misreading



...Ok don't worry Jake beat me to it
« Last Edit: October 20, 2016, 07:55:12 pm by RuiAce »

MysteryMarker

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Re: Mathematics Question Thread
« Reply #704 on: October 20, 2016, 07:57:57 pm »
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Hey, I came across this question and realised that I have absolutely no idea what simple interest is. Could someone explain to me the last part of this question, the parts before are fine just the last part. The answers used some PRT/100 = I formula, which i have never used lol.


Cheers :P