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March 30, 2024, 12:10:58 am

Author Topic: Mathematics Question Thread  (Read 1297219 times)  Share 

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jamonwindeyer

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Re: Mathematics Question Thread
« Reply #90 on: May 14, 2016, 05:37:45 pm »
+3







Optionally, you can add a comment about the fact that a $250 000 dollar mortgage is totally unrealistic for first home buyers in Sydney  ;)

Totally kidding, though it might give the marker a laugh.

ccarolineb

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Re: Mathematics Question Thread
« Reply #91 on: May 23, 2016, 08:32:57 pm »
0
Struggling to understand how to do this!

- a population in a certain city is growing at a rate proportional to the population itself. after 3 years the population increases by 20%. How long will it take for the population to double?

RuiAce

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Re: Mathematics Question Thread
« Reply #92 on: May 23, 2016, 08:58:10 pm »
0
Struggling to understand how to do this!

- a population in a certain city is growing at a rate proportional to the population itself. after 3 years the population increases by 20%. How long will it take for the population to double?
Inserted an edit to make Jamon's point a bit clearer. Let A=P0




« Last Edit: May 24, 2016, 09:06:46 am by RuiAce »

jakesilove

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Re: Mathematics Question Thread
« Reply #93 on: May 23, 2016, 09:20:24 pm »
0
Optionally, you can add a comment about the fact that a $250 000 dollar mortgage is totally unrealistic for first home buyers in Sydney  ;)

Totally kidding, though it might give the marker a laugh.

This caused me much pain
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jamonwindeyer

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Re: Mathematics Question Thread
« Reply #94 on: May 23, 2016, 09:31:33 pm »
0






As an elaboration for you Caroline, in case you are still getting used to this style of problem, 'A' represents the initial value of the quantity in question (in this case, the population). You can prove this by substituting t=0 if you so choose, but Rui's solution is what you'd do in the HSC exam, a very standard process  ;D

angela99

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Re: Mathematics Question Thread
« Reply #95 on: May 24, 2016, 06:43:22 pm »
0
Topic: Applications of Calculus to the Physical World
Sub-topic: Exponential growth and decay
Formulas: Q = Ae^kt, dQ/dt = kQ

Can you help with this question please? not having obvious numbers to substitute into the formula is really throwing me off  ???

The half-life of radium is
1600 years.
(a) Find the percentage of radium that will be decayed after 500 years.
(b) Find the number of years that it will take for 75% of the radium to decay.

Thank you!  :)  :) 

jakesilove

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Re: Mathematics Question Thread
« Reply #96 on: May 24, 2016, 07:51:43 pm »
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Topic: Applications of Calculus to the Physical World
Sub-topic: Exponential growth and decay
Formulas: Q = Ae^kt, dQ/dt = kQ

Can you help with this question please? not having obvious numbers to substitute into the formula is really throwing me off  ???

The half-life of radium is
1600 years.
(a) Find the percentage of radium that will be decayed after 500 years.
(b) Find the number of years that it will take for 75% of the radium to decay.

Thank you!  :)  :)

Hey! This is a standard method for exponential growth/decay questions that don't give you actual numbers, but rather percentages. You need to just LET Q equal something at time t=0 (eg. 100, like I used, or 1, which is what I usually used). Then, as time progresses, you just use an appropriate percentage of your original value. The explanation in the answer below should explain what I mean; once you've seen it once, you'll be able to do it again in a heartbeat!



Jake
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angela99

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Re: Mathematics Question Thread
« Reply #97 on: May 24, 2016, 08:10:28 pm »
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Hey! This is a standard method for exponential growth/decay questions that don't give you actual numbers, but rather percentages. You need to just LET Q equal something at time t=0 (eg. 100, like I used, or 1, which is what I usually used). Then, as time progresses, you just use an appropriate percentage of your original value. The explanation in the answer below should explain what I mean; once you've seen it once, you'll be able to do it again in a heartbeat!

(Image removed from quote.)

Jake

Thank you!!

angela99

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Re: Mathematics Question Thread
« Reply #98 on: May 27, 2016, 12:08:51 pm »
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PLEASE HELP!! THANK YOU!

Find, correct to 2 decimal places, the area enclosed by the curve
y = log2 x, the x-axis and the lines x = 1 and x = 3 by using simpson’s rule with 3 function values.

angela99

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Re: Mathematics Question Thread
« Reply #99 on: May 27, 2016, 12:11:43 pm »
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log2 is log base 2 btw

jakesilove

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Re: Mathematics Question Thread
« Reply #100 on: May 27, 2016, 01:08:38 pm »
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PLEASE HELP!! THANK YOU!

Find, correct to 2 decimal places, the area enclosed by the curve
y = log2 x, the x-axis and the lines x = 1 and x = 3 by using simpson’s rule with 3 function values.

Hey! I've attached my answer below :) It's really important that you are comfortable using Simpson's rule, and I think it is also on your formula sheet in case you forget it. Just break up your area into the number of subdivisions you require, figure out the distance between each division, and then sub the values straight into the formula! For a comparison, the 'real' answer should be 1.87, so this is pretty damn close!



Jake
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Anika1098

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Re: Mathematics Question Thread
« Reply #101 on: May 28, 2016, 10:28:16 pm »
0
Hey Jake, sorry to bother you but we got this massive revision booklet for my test recently, but we are not allowed to ask our teachers for awnsers or anything and there are a few questions (a lot) that I'm really struggling to Understand?

1 b ii
8 a iii
10 b
14 c ii
16 b iii
17 iii Iv
18 b i ii
20
22 a iii d ii e i ii iii

I understand there are heaps so please just pick one or two that suit you best?
Here are thre questions; sorry about my dodgy af collage.

jakesilove

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Re: Mathematics Question Thread
« Reply #102 on: May 28, 2016, 11:12:11 pm »
0
Hey Jake, sorry to bother you but we got this massive revision booklet for my test recently, but we are not allowed to ask our teachers for awnsers or anything and there are a few questions (a lot) that I'm really struggling to Understand?

1 b ii
8 a iii
10 b
14 c ii
16 b iii
17 iii Iv
18 b i ii
20
22 a iii d ii e i ii iii

I understand there are heaps so please just pick one or two that suit you best?
Here are thre questions; sorry about my dodgy af collage.

Hey!

Unfortunately I can't decipher the questions you've sent over, they are way too blurry. If you could either send higher quality pictures, or just type up the important ones, that would be great! I'm happy to help with things that you're struggling with, but maybe do try to limit the questions to like one of each type. That way, hopefully I can help explain the general way to solve those kinds of questions, and then you can figure out the others yourself.

Jake
ATAR: 99.80

Mathematics Extension 2: 93
Physics: 93
Chemistry: 93
Modern History: 94
English Advanced: 95
Mathematics: 96
Mathematics Extension 1: 98

Studying a combined Advanced Science/Law degree at UNSW

RuiAce

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Re: Mathematics Question Thread
« Reply #103 on: May 28, 2016, 11:31:05 pm »
0
Hey Jake, sorry to bother you but we got this massive revision booklet for my test recently, but we are not allowed to ask our teachers for awnsers or anything and there are a few questions (a lot) that I'm really struggling to Understand?

1 b ii
8 a iii
10 b
14 c ii
16 b iii
17 iii Iv
18 b i ii
20
22 a iii d ii e i ii iii

I understand there are heaps so please just pick one or two that suit you best?
Here are thre questions; sorry about my dodgy af collage.
Hey!

Unfortunately I can't decipher the questions you've sent over, they are way too blurry. If you could either send higher quality pictures, or just type up the important ones, that would be great! I'm happy to help with things that you're struggling with, but maybe do try to limit the questions to like one of each type. That way, hopefully I can help explain the general way to solve those kinds of questions, and then you can figure out the others yourself.

Jake
Or maybe just a larger collage.

This is the solution to the only clear question.


itswags98

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Re: Mathematics Question Thread
« Reply #104 on: June 26, 2016, 09:12:59 pm »
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Hey Jake, sorry to bother you but we got this massive revision booklet for my test recently, but we are not allowed to ask our teachers for awnsers or anything and there are a few questions (a lot) that I'm really struggling to Understand?

Must be a pretty dodgy teacher if ur not allowed to ask them questions
Goal of 85 ATAR. Lets do eht