WitCH 49: Trigged Again

The question below is from the second 2020 Specialist exam (not online), and was flagged by commenter John Friend in the discussion here. John has spelled out the problems, but the question is bad enough to warrant its own post, and there’s arguably a little more to be said.

MitPY 10: Square Roots

This MitPY comes from a student, Jay:

I have a question relating to polynomial equations. For context I have just finished Y11 during which I completed Further 3&4, Methods 1&2 and Specialist 1&2.

This year during my maths methods class we covered the square root graph, however I was confused as to why it only showed the positive solutions. When I asked about it I was told it was because the radical symbol meant only the positive solution.

However since then I have learnt that the graph of \boldsymbol{y=x^{0.5}} also only shows the positive solution of the square root, while \boldsymbol{y^2=x} shows both. I am quite confused by why they aren’t the same. The only reason that I could think of is that it would mean \boldsymbol{y=x^2} would be the same as \boldsymbol{y^2=x^4}, and while the points (-2,-4) and (2,-4) fit the latter they clearly don’t fit former.

Could you please explain why these aren’t the same?

WitCH 47: A Bad Inflection

The question below is from the first 2020 Specialist exam (not online). It has been discussed in the comments here, and the main issues have been noted, but we’ve decided the question is sufficiently flawed to warrant its own post.

UPDATE (10/09/21) For those who’d placed a wager, the examination report (Word-doc-VCAA-stupid) indicates that a second derivative argument was expected. Hence, thousands of VCE students no longer have any sense of what VCAA means by “hence”.

Feeling VCAA’s Draft: Discussion

It seems the VCAA has just released their draft of the new study design for Mathematics:

  • The current (pre-COVID) study design (pdf) is here.
  • The draft for the new study design (word) is here.
  • The key changes overview (work) is here.
  • The link for feedback (until March 9, 2021) is here.

We haven’t yet looked at the draft, because we’re scared. But, don’t let that stop others. May the discussion and the throwing of brickbats begin.

UPDATE (09/03/21)

We’ve written a post with some brief thoughts here.

Secret Specialist Business: Exam 2 Discussion

This is our post for teachers and students to discuss Specialist Exam 2 (not online). There are also posts for Methods Exam 1, Methods Exam 2 and Specialist Exam 1.

UPDATE (11/09/21) The examination report is here (Word-VCAA-stupid). Corresponding updates, are included with the associated question, in green, and see also here, here and here.

UPDATE (31/12/20) The exam is now online. Continue reading “Secret Specialist Business: Exam 2 Discussion”

Secret Specialist Business: Exam 1 Discussion

This is our post for teachers and students to discuss Specialist Exam 1 (not online). There are also posts for Methods Exam 1, Methods Exam 2 and Specialist Exam 2.

UPDATE (10/09/21) The examination report is here (a Word document, because it’s stupider). Corresponding updates, are included with the associated question, in green, and see also here and here. Continue reading “Secret Specialist Business: Exam 1 Discussion”

An Offer: Checking For SACking Offences

Pauline Baynes

This is an open offer to review Methods and Specialist SACs. Here are the conditions:

0) The review is free. (You can consider donating to Tenderfeet.)

1) You may email me any Methods or Specialist SAC, by anyone.

2) You should indicate whether or not you are the writer of the SAC.

3) If you are the writer of the SAC, I will be diplomatic.*

4) It’s on your head, in particular for future SACs, if you’re breaking confidentiality rules or conventions. This is not my concern.

5) I will keep all SACs confidential, except to the extent there is explicit agreement otherwise. (See 12-14, below.)

6) Future SACs should, at minimum, be close to a final draft.

7) All SACs should include solutions and a grading scheme.

8) I may decline to review a SAC for being too old, or for other reasons.

9) I will review only for mathematical sense and mathematical correctness.

10) In particular, I will not check for, and do not give a stuff about, VCAA compliance.

11) I will not check all arithmetic and a review should not be taken as a guarantee that the SAC is error-free.

12) Each time I review a SAC I will record so below, with brief and, modulo points 13 and 14, anonymity-preserving comments.

13) I will identify commercial SACs as such, possibly indicating the commercial entity.

14) If you are the author of the SAC and you agree, I will consider making a separate post, to review the SAC in detail and to allow for comment.

 

I will be interested to see who is brave enough to enter (and who is tossed into) the lion’s den.

 

*) Yes, I am capable of diplomacy. I just prefer to do without.

UPDATE (26/7)

We have our first taker: a brave soul has entered the den. I’ll look at the proffered SAC asap. I was also asked what I am after, in making this offer, which is a fair question. The answer is two-fold:

a) (Jekyll) I’m making a genuine offer to provide a critique of a SAC from a mathematical perspective, for any writer who wants it. I’m hoping that by providing such a critique, the writer will become more attuned to any mathematical shortcomings in their (and all) SACs, and in VCE generally. Hopefully then, to the limited extent that VCAA’s idiot curriculum permits it, this will help the writer produce more mathematically coherent and rich SACs in the future.

b) (Hyde) I’m looking to see as much as I can of the nonsense the SAC system is producing. This will allow me to confirm for any teacher or student who has been served swill that they have indeed been served swill. It will also allow me to write upon such SACs, even if in very oblique terms.

UPDATE (27/7)

OK, this post is being steered away from what I intended, but I’m happy to let others steer.

First, a clarification. By “SAC”, I mean any school-based Year 12 assessment that counts towards the final VCE grade. I don’t care if the assessment takes five minutes or five days.

Now, the question is what to do with SACs offered to me by authors? I have two currently. I can either

a) Make the SACs into posts on this blog. The SACs would then be a basis for discussion, and a model for future SACs, but the SACs themselves would presumably not be usable. (Again, I don’t give a stuff about protocol, but obviously teachers must.)

or

b) Keep the SACs off the site, except for brief comments below, and set up a Free SACs to Good Home post. Teachers can then contact me to obtain copies.

Readers can suggest to me what they prefer. They can also suggest how (b) might work in practice.