Mathematics Extension 1 Exam Thoughts (2 Viewers)

[HashtagManthan]

What do you guys think a 50/70 (71.4%) will align to?

 

[photastic]

What do you guys think a 50/70 (71.4%) will align to?

High 70s to low 80s

 

[le_420_prince]

Wondering this too. I'm at 70/70 raw, though I tried to simplify the integral by substitution result and did it incorrectly, if they decide to take that as my answer instead of the perfectly valid result I had before it then I'm at 69/70. Though I'm ranked 2nd internally and I don't know if I can depend on another 69 or 70 so it would be nice to know if either of us have a chance.

yeah dude same algebraic error on last question im 2nd internal at ruse so would probs be getting 100 school mark but my external is gonna knock me down outta that 70/70 range

 

[le_420_prince]

Assuming that more than 10 people score 70/70 with top ranks, how do they chose the 10 who get state rank and the person who gets first?

apparantly they look at the elegance of your proofs etc

 

[leehuan]

Can someone please explain to me why Q12 c) was from the 2006 4U paper?

 

[Carrotsticks]

Can someone please explain to me why Q12 c) was from the 2006 4U paper?

That was more so a lead up for part (ii), which was presumably the focus of the question. As well as 2006 being an exceptionally easy paper, that question IMO should not even be anywhere near Question 7.

 

[Carrotsticks]

Also, I have completed my detailed solutions, and they can be found here.

http://community.boredofstudies.org...lutions-hsc-2016-extension-1-mathematics.html

 

[tommo727]

Would I get a mark for finding coordinates for R in 14 ii) of the parabola question?

 

[leehuan]

That was more so a lead up for part (ii), which was presumably the focus of the question. As well as 2006 being an exceptionally easy paper, that question IMO should not even be anywhere near Question 7.

I do agree that it shouldn't have been in a Q7 of 4U because it wasn't that hard.

Even if it is a lead-up, though, it still advantages 4U students. Not gonna fuss excessively because it's not huge but it still gives them an advantage, because no 3U student would (under normal circumstances) touch that paper whereas 4U people just got 2 free marks.

 

[tommo727]

That was more so a lead up for part (ii), which was presumably the focus of the question.

The newtons method had nothing to do with it though did it?

 

[Carrotsticks]

The newtons method had nothing to do with it though did it?

I was referring to the 2006 paper. But you are correct, in the 2016 paper part (ii) had nothing to do with it.

 

[T-R-O-L-O-L]

Would I get a mark for finding coordinates for R in 14 ii) of the parabola question?

I did the exact same thing, I'm hoping for at least 1 out of 3.

 

[pikachu975]

Assuming that more than 10 people score 70/70 with top ranks, how do they chose the 10 who get state rank and the person who gets first?

I think they look at your marks in the other levels of maths.

 

[KingOfActing]

Circle geometry part 2 can go die

I also misread one of the multiple choice (didn't see the word "Reflex" </3) and I must've made an algebraic mistake on the very last question, so I'm estimating 66/70 for myself.

 

[InteGrand]

Also for 9, am I the only person who literally measured the gradient of the tangent with a ruler?

Don't really need to measure any slopes. The reason I thought it was (A) was that f''(1) looked like 0 (inflexion), so f''(1) had to be smallest. (This narrows it down to between (A) and (B).) Assuming this then, it is also clear that f"(x) >= 0 for 0 < x < 1. So the slope at the right endpoint of the interval [0,1], namely f'(1), must be greater than the slope of the secant line joining the points on the graph at the endpoints (this is visually clear, and also follows from the Mean Value Theorem, which iirc was proved in this year's 3U BOS Trial). But the slope of this secant line is just (f(1) - 0)/(1 - 0) = f(1), and the only option between (A) and (B) that has f'(1) > f(1) is (A). So the answer is (A).

I don't think we can actually just deduce from that graph that it is necessarily the case that f'(1) > 1 (unless they meant for you to interpret it as to scale and measure it, which is not usually what HSC 3U/4U does). The Q. should have said which is a possible correct answer (only (A) is).

 

[gandalfbrah]

What would 85-90ish scale to?


Sent from my iPhone using Tapatalk

 

[ProdigyInspired]

What would 85-90ish scale to?


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Easily an E4.

 

[calamebe]

Don't really need to measure any slopes. The reason I thought it was (A) was that f''(1) looked like 0 (inflexion), so f''(1) had to be smallest. (This narrows it down to between (A) and (B).) Assuming this then, it is also clear that f"(x) >= 0 for 0 < x < 1. So the slope at the right endpoint of the interval [0,1], namely f'(1), must be greater than the slope of the secant line joining the points on the graph at the endpoints (this is visually clear, and also follows from the Mean Value Theorem, which iirc was proved in this year's 3U BOS Trial). But the slope of this secant line is just (f(1) - 0)/(1 - 0) = f(1), and the only option between (A) and (B) that has f'(1) > f(1) is (A). So the answer is (A).

I don't think we can actually just deduce from that graph that it is necessarily the case that f'(1) > 1 (unless they meant for you to interpret it as to scale and measure it, which is not usually what HSC 3U/4U does). The Q. should have said which is a possible correct answer (only (A) is).

Oh yeah I got that about f''(x), so I did narrow it down to A and B, but then I just measured the gradient of f'(1) to make sure it was greater than 1. Yeah that makes sense, with the secant line, didn't think of that.

 

[trecex1]

Circle geometry part 2 can go die

I also misread one of the multiple choice (didn't see the word "Reflex" </3) and I must've made an algebraic mistake on the very last question, so I'm estimating 66/70 for myself.

I feel like I got 66 as well really hoping for an extra sympathy mark for misreading a question but I doubt it. Do you think 66/70 will align to 98?

 

[eating]

Estimates for the raw mark necessary for 80 or 90 adjusted? (ie. E3.5 and E4 cutoff)