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 STPM 2014/2015

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Just Visiting By
post Feb 20 2015, 03:19 PM

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QUOTE(RED-HAIR-SHANKS @ Feb 20 2015, 03:08 PM)
Oh...

But then, just a while ago I turned to my senior for advice pertaining to this question and he told me that we can apply trigonometry to solve cubic equation, as well as a formula by Lodovico Ferrari to even solve quartic equations(fourth degree polynomial). And he added that there is virtually no further algebraic solutions for polynomial with degree higher than 5, I forgot it but I think it's called Abel–Ruffini theorem.

I'm not learning all of them though. I'm having trouble with numerical methods of cubic equation for now so I'll just stick to that.
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I think for now you can ignore all those gobbledygooks. The highest order of polynomial I have ever encountered is only 4, so I can't comment on the higher powers. But for STPM, you do not need any thing else that it outside STPM syllabus.

RED-HAIR-SHANKS
post Feb 20 2015, 03:50 PM

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QUOTE(Just Visiting By @ Feb 20 2015, 03:19 PM)
I think for now you can ignore all those gobbledygooks. The highest order of polynomial I have ever encountered is only 4, so I can't comment on the higher powers. But for STPM, you do not need any thing else that it outside STPM syllabus.
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About the bolded part in your above statement, does it holds true for Maclaurin series too?? My teacher gave us a few practices on that chapter, and 1 question required us to obtain the Maclaurin expansion up to and including x⁵! The steps were extremely tedious and taxing for me, and I usually made careless mistakes in when it comes to expanding.
Just Visiting By
post Feb 20 2015, 04:40 PM

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QUOTE(RED-HAIR-SHANKS @ Feb 20 2015, 03:50 PM)
About the bolded part in your above statement, does it holds true for Maclaurin series too?? My teacher gave us a few practices on that chapter, and 1 question required us to obtain the Maclaurin expansion up to and including x⁵! The steps were extremely tedious and taxing for me, and I usually made careless mistakes in when it comes to expanding.
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For Maclaurin series, the highest derivative I've ever encountered is 6, and it involved differentiating tan. Haha so you can imagine how tedious it is!

Maclaurin Series is actually very simple, you just have to be very careful so that you don't make mistakes as then it is very difficult for you to trace back where you did wrong.
Critical_Fallacy
post Feb 20 2015, 06:04 PM

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QUOTE(RED-HAIR-SHANKS @ Feb 20 2015, 03:08 PM)
I'm not learning all of them though. I'm having trouble with numerical methods of cubic equation for now so I'll just stick to that.
Since Cardano's formula is not covered in STPM, you can simply use CASIO fx570 to get the roots of the cubic equation. Unless you are instructed to apply Newton-Raphson's method to find the root, I believe you can just use the built-in feature in the CASIO calculator. STPM Pure Math is still relatively straightforward. icon_rolleyes.gif
Critical_Fallacy
post Feb 20 2015, 06:30 PM

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QUOTE(RED-HAIR-SHANKS @ Feb 20 2015, 01:42 PM)
I've looked around for Cardano's Formula, and I'm learning on how to use it. However, my workings reached to a stalemate when I was calculating for u³+v³.
Stick to STPM Math as what Just Visiting By advised. Cardano's formula is intended for those who are into the real "Pure Maths", by which a cubic equation is solved analytically.

In fact, I'm more worried about the way you interpret the math problems like the third (iii) problem. The techniques you apply to solve a problem reflect your understanding of what the question requires you to do.

While (iii) was designed to test your algebraic manipulation skill and your critical thinking skill to relate the cubic equation to the rational function, did you realize that (iii) also could be solved by obtaining the roots of x³ – 6x – 1 = 0? unsure.gif

This post has been edited by Critical_Fallacy: Feb 20 2015, 06:37 PM
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post Feb 20 2015, 07:13 PM

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QUOTE(Critical_Fallacy @ Feb 20 2015, 06:30 PM)
Stick to STPM Math as what Just Visiting By advised. Cardano's formula is intended for those who are into the real "Pure Maths", by which a cubic equation is solved analytically.

In fact, I'm more worried about the way you interpret the math problems like the third (iii) problem. The techniques you apply to solve a problem reflect your understanding of what the question requires you to do.

While (iii) was designed to test your algebraic manipulation skill and your critical thinking skill to relate the cubic equation to the rational function, did you realize that (iii) also could be solved by obtaining the roots of x³ – 6x – 1 = 0? unsure.gif
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I haven't got the clue on which equation to pick, and most importantly, I never truly fathom on why x³ – 6x – 1 = 0 is picked in this case, instead of user posted image.

No, I did not realize that.
Critical_Fallacy
post Feb 20 2015, 09:43 PM

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QUOTE(RED-HAIR-SHANKS @ Feb 20 2015, 07:13 PM)
I haven't got the clue on which equation to pick, and most importantly, I never truly fathom on why x³ – 6x – 1 = 0 is picked in this case, instead of user posted image.

No, I did not realize that.
It doesn't matter which equation you pick.

user posted image

Because it is derived from the fundamental cubic equation f(x) = 0, they all have the same set of solutions.

user posted image

Check the intersections of the graphs.

user posted image

This post has been edited by Critical_Fallacy: Feb 20 2015, 09:45 PM
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post Feb 20 2015, 10:06 PM

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QUOTE(Critical_Fallacy @ Feb 20 2015, 09:43 PM)
It doesn't matter which equation you pick.

user posted image

Because it is derived from the fundamental cubic equation f(x) = 0, they all have the same set of solutions.

user posted image

Check the intersections of the graphs.

user posted image
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Oh, now I get it, I even manipulated the equation in my previous Third problem(iii).

When the (blue)graph of function h(x)=x³ – 6x – 1 =0, the graph cuts the x-axis at 3 different x-coordinates, which are x₁=-2.362, x₂=-0.1675, x₃=2.5289.
chocobo7779
post Feb 21 2015, 09:33 PM

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QUOTE(RED-HAIR-SHANKS @ Feb 20 2015, 10:06 PM)
Oh, now I get it, I even manipulated the equation in my previous Third problem(iii).

When the (blue)graph of function h(x)=x³ – 6x – 1 =0, the graph cuts the x-axis at 3 different x-coordinates, which are x₁=-2.362, x₂=-0.1675, x₃=2.5289.
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You did a pretty good job on answering my challenge, but here are the correct answer:

https://www.dropbox.com/s/k8k4n5t9c8i70kz/Book1.xlsx?dl=0
RED-HAIR-SHANKS
post Feb 21 2015, 10:33 PM

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QUOTE(chocobo7779 @ Feb 21 2015, 09:33 PM)
You did a pretty good job on answering my challenge, but here are the correct answer:

https://www.dropbox.com/s/k8k4n5t9c8i70kz/Book1.xlsx?dl=0
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No, I don't think I answered your question correctly, and if anything, I totally misinterpreted your previous question.

Thank you for the solution.
Critical_Fallacy
post Feb 22 2015, 01:01 AM

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QUOTE(RED-HAIR-SHANKS @ Feb 21 2015, 10:33 PM)
No, I don't think I answered your question correctly, and if anything, I totally misinterpreted your previous question.
THe solution provided by chocobo7779 is similar to the Bisection method—simple but slow to converge.

From the practical side, because the cubic function is continuously differentiable, Newton–Raphson method (covered in STPM) is highly recommended.

user posted image

To answer chocobo7779's challenge without using calculus, I have modified an optimization method (to find the extremum) to locate the root that is known to exist within a certain interval.

user posted image

The results converge to 2.5289 (4 d.p).
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post Feb 22 2015, 11:19 AM

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QUOTE(Critical_Fallacy @ Feb 22 2015, 01:01 AM)
THe solution provided by chocobo7779 is similar to the Bisection method—simple but slow to converge.

From the practical side, because the cubic function is continuously differentiable, Newton–Raphson method (covered in STPM) is highly recommended.

user posted image

To answer chocobo7779's challenge without using calculus, I have modified an optimization method (to find the extremum) to locate the root that is known to exist within a certain interval.

user posted image

The results converge to 2.5289 (4 d.p).
*
Oh, thank you for your solution. But, it looks much complex than the Bisection method and Newton–Raphson method.
Critical_Fallacy
post Feb 22 2015, 01:32 PM

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QUOTE(RED-HAIR-SHANKS @ Feb 22 2015, 11:19 AM)
Oh, thank you for your solution. But, it looks much complex than the Bisection method and Newton–Raphson method.
This is the full version algorithm of chocobo7779's method. It requires at least 50 iterations and a series of tests to arrive at the accuracy of 5 decimal places. Compared to the Modified Golden Section Search, the rate of convergence is much slower. Of course, both cannot beat Newton–Raphson method. sweat.gif

user posted image
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post Feb 22 2015, 10:16 PM

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Just Visiting By, can you recommend me some good sites on where I can find the literature review for my Physics assignment? My assignment revolves around the Interference of Sound Waves. I'm in a muddle here, because my teacher informed me a few days ago that without an adequate literature review, I will be coerced to switch my title of experiment. Now, I'm halfway done on Abstract, Theory, Problem Statement, Objectives and Methodology.

My friends and I went to USM last December to find some stuffs pertaining to our Physics/Chemistry assignments and we already took some photos for our bibliography, so that just leaves us with literature review and and a few more components(Observations, Discussions...). And yes, my friend and I did searched the Internet for days, and we found a handful of literature reviews, but they weren't related with our assignments. We could hardly find any suitable samples from ResearchGate and Scribd. It will be really appalling to restart our Physics assignment all over again back to square one.

Thanks in advance.
sagethesausage
post Feb 23 2015, 12:14 AM

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QUOTE(RED-HAIR-SHANKS @ Feb 17 2015, 09:53 PM)
stickmanchong17, sagethesausage and scgoh123, this is the timetable for our second term STPM 2014/2015 examination.
user posted image

We're roughly 89 days away from our second term exam, so 加油吧!
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Thanks for the reminder. It's already way below the 100 days mark and yet I don't feel ready at all.

regan96
post Feb 23 2015, 10:30 AM

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icon_question.gif icon_question.gif icon_question.gif

This post has been edited by regan96: Feb 23 2015, 10:31 AM
regan96
post Feb 23 2015, 10:31 AM

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Does anybody know how to do the metodologi. My teacher ask us to try first but i dont even know what to write and all my classmates are bust with chinese new year. I am the only indian in that class smile.gif icon_question.gif icon_question.gif icon_question.gif rclxub.gif rclxub.gif
maximR
post Feb 24 2015, 01:23 PM

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» Click to show Spoiler - click again to hide... «


There are tons of free scientific literature, university lecture notes, and archived books available online. Search carefully. Type 'sound interference pdf' and you'll find a lot of good ones. Tip: Type something, then 'pdf', chances are you'll find quite a few good university lecture notes.

Just Visiting By
post Feb 24 2015, 03:44 PM

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QUOTE(RED-HAIR-SHANKS @ Feb 22 2015, 10:16 PM)
Just Visiting By, can you recommend me some good sites on where I can find the literature review for my Physics assignment? My assignment revolves around the Interference of Sound Waves. I'm in a muddle here, because my teacher informed me a few days ago that without an adequate literature review, I will be coerced to switch my title of experiment. Now, I'm halfway done on Abstract, Theory, Problem Statement, Objectives and Methodology.

My friends and I went to USM last December to find some stuffs pertaining to our Physics/Chemistry assignments and we already took some photos for our bibliography, so that just leaves us with literature review and and a few more components(Observations, Discussions...). And yes, my friend and I did searched the Internet for days, and we found a handful of literature reviews, but they weren't related with our assignments. We could hardly find any suitable samples from ResearchGate and Scribd. It will be really appalling to restart our Physics assignment all over again back to square one.

Thanks in advance.
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Sorry for the late reply.

I don't know any websites that provide literature review.

And I've sadly lost my chemistry project document so I am afraid I can't help. Sorry.

By the way, why did you guys go to USM? Your school doesn't allow you all to bring camera to school for the project?
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post Feb 24 2015, 06:53 PM

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QUOTE(maximR @ Feb 24 2015, 01:23 PM)
» Click to show Spoiler - click again to hide... «


There are tons of free scientific literature, university lecture notes, and archived books available online. Search carefully. Type 'sound interference pdf' and you'll find a lot of good ones. Tip: Type something, then 'pdf', chances are you'll find quite a few good university lecture notes.
*
Thanks for the tip. I'll try look them up.

QUOTE(Just Visiting By @ Feb 24 2015, 03:44 PM)
Sorry for the late reply.

I don't know any websites that provide literature review.

And I've sadly lost my chemistry project document so I am afraid I can't help. Sorry.

By the way, why did you guys go to USM? Your school doesn't allow you all to bring camera to school for the project?
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It's alright, we still have some time left.

Simply because we could find lots of information and materials pertaining to our experiments and assignments in Physics, Chemistry and Biology. Our school library didn't help. I must say that I'm really amazed by some of the huge collections of books in USM's library. My teacher deemed it redundant to bring cameras to school just for the sake of our projects, she added that her smartphone will do the job for us.

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