Implicit D (1 Viewer)

[Joshmosh2]

For 3u, is implicit differentiation a viable method for finding dx/dy
i.e. is it accepted in the HSC

 

[Silly Sausage]

It's not in the syllabus so I wouldn't do it in the HSC. You can ask your teacher if you can for internal assessments OR you can do can do it discreetly e.g. Do it on a scrap piece of paper or something like that.

 

[Drsoccerball]

Maybe to check your answer

 

[HecticSandWitch]

It's not in the syllabus so I wouldn't do it in the HSC. You can ask your teacher if you can for internal assessments OR you can do can do it discreetly e.g. Do it on a scrap piece of paper or something like that.

Keep it on the hush ahahha. The dirty secret that is implicit differentiation.

 

[braintic]

It's not in the syllabus so I wouldn't do it in the HSC. You can ask your teacher if you can for internal assessments OR you can do can do it discreetly e.g. Do it on a scrap piece of paper or something like that.

Implicit differentiation is definitely allowable. From the official marker's comments to Q3c of the 2004 HSC: "Some candidates successfully used implicit differentiation methods".

 

[SilentWaters]

I agree. 4 unit methods are quite often acknowledged in marker's comments. The only caveat being that many get too ambitious and misuse them, leading to remarks like "candidates tried to use Extension 2 methods where Extension 1 methods would have sufficed, resulting in convoluted scripts that led no where".

 

[mreditor16]

Implicit differentiation is definitely allowable. From the official marker's comments to Q3c of the 2004 HSC: "Some candidates successfully used implicit differentiation methods".

I agree. 4 unit methods are quite often acknowledged in marker's comments. The only caveat being that many get too ambitious and misuse them, leading to remarks like "candidates tried to use Extension 2 methods where Extension 1 methods would have sufficed, resulting in convoluted scripts that led no where".

+1 these guys. Would just like to add that the examiners will set the 3U paper such that the question can be done using solely 3U (and 2U) methods. However, feel free to use implicit differentiation, especially when checking your answers. As mentioned by SilentWaters, don't become too ambitious with your use of it - sometimes, it can overcomplicate questions which have a much simpler, quicker solution to it.

 

[braintic]

+1 these guys. Would just like to add that the examiners will set the 3U paper such that the question can be done using solely 3U (and 2U) methods. However, feel free to use implicit differentiation, especially when checking your answers. As mentioned by SilentWaters, don't become too ambitious with your use of it - sometimes, it can overcomplicate questions which have a much simpler, quicker solution to it.

Adding to that, examiners don't like students using concepts from beyond the Ext 2 syllabus.

For example, they won't pay L'Hospital's rule (which many people learn at tutoring) unless it comes with a full explanation of how it works and why it is applicable to use in that particular question.

 

[InteGrand]

Adding to that, examiners don't like students using concepts from beyond the Ext 2 syllabus.

For example, they won't pay L'Hospital's rule (which many people learn at tutoring) unless it comes with a full explanation of how it works and why it is applicable to use in that particular question.

But 2009 HSC Mathematics Extension 1 Notes from Marking Centre says: '...Those who used l’Hopital’s rule were usually successful.' (Page 4, Question 1(c) in the Notes document: http://www.boardofstudies.nsw.edu.au/hsc_exams/hsc2009exams/notes/mathematics-ext1-notes-09.pdf )

Edit: It was for a 1-mark question though, so maybe only the final answer mattered.

 

[Kaido]

^ I'm surprised you actually found that

 

[InteGrand]

Adding to that, examiners don't like students using concepts from beyond the Ext 2 syllabus.

For example, they won't pay L'Hospital's rule (which many people learn at tutoring) unless it comes with a full explanation of how it works and why it is applicable to use in that particular question.

Just curious, what kind of "full explanation of how it works" do they expect? A formal proof of it?

Or just saying that the limit is equal to the limit if the numerator and denominator are replaced by their derivatives and the conditions required etc. (in other words, a statement of the theorem)?

 

[braintic]

Just curious, what kind of "full explanation of how it works" do they expect? A formal proof of it?

Or just saying that the limit is equal to the limit if the numerator and denominator are replaced by their derivatives and the conditions required etc. (in other words, a statement of the theorem)?

I am quoting people who went to the 2013 HSC Examiner's day (not sure if its called that, and not 100% sure I have the right year).
The head examiners tell attendees how the question that they were responsible for was marked.
As I wasn't there, I'm not sure how much detail they went into, but the gist of the message was passed on to me.