Mathematics Extension 1 Exam Thoughts (1 Viewer)

WrittenLoveLetters

배고파
Did you try to scab some partial marks? I know for induction if you prove the "true for x=1" and "assume true for n=k" then I believe that's 2 marks without actually doing work. (maybe just 1?)
For that question, I did both of what you said - I even tried to prove it. I tried though! I actually did get to Q14 and just did the 1st page of it. Had to drop my pen at Q14C. For most questions, I had working out that tried to work towards the correct solution - but alas, still a lot of marks that I'm not confident in and that I lost I'm not happy that I don't feel like I beat my trials mark and improved though.

Just wondering, would say that doing 4u significantly improves your 3u? If so for what reasons? Does 4u significantly improve your problem solving a skills or is it because specific 4u methods make 3u question less difficult?
I don't do 4U. I am a pure 3U student. From what I know, the 4U kids in my class have a passion for it - heck, duo 1st place finds maths so exciting when the questions get insanely hard for them.

we've been found out guys!
!!!

MorrisTheHorris

New Member
What did everyone get for the very last question, the values of t?
I got plus or minus sqrt(2). Have confirmed it in Geogebra, quite confident.

eating

Wannabe COMP god
Just wondering, would say that doing 4u significantly improves your 3u? If so for what reasons? Does 4u significantly improve your problem solving a skills or is it because specific 4u methods make 3u question less difficult?
I don't think any specific 4u methods were helpful (or even could be used?). I think it's like asking if 3u methods help 2u questions.

I believe it comes down to:
1) if you have 4 units of maths, you will (probably) practice more and do more questions of harder difficult. We get 3u questions in 4u as well.
2) if you are great at maths, you will most likely do 4u. Cause rather than effect.

calamebe

Active Member
I got plus or minus sqrt(2). Have confirmed it in Geogebra, quite confident.
Same here. I was scared as my friend said plus or minus root 2 on 2 but yeah if you confirmed it there that's good. But he beat me internally

eating

Wannabe COMP god
What did everyone get for the very last question, the values of t?
I got, for the question before, a focal length of "(a-a^2)/4", or the other way around. Did I screw up?

Couldn't get the last one out.

ProdigyInspired

Just wondering, would say that doing 4u significantly improves your 3u? If so for what reasons? Does 4u significantly improve your problem solving a skills or is it because specific 4u methods make 3u question less difficult?
I would say so.
- You explore harder concepts which somewhat branch off 3u topics. This then translates into doing harder questions and how you think about them. When I do 3u I somewhat dumb down what I think the answer would be so I don't overcomplicate it.

Another factor is the more practice time.

calamebe

Active Member
I got, for the question before, a focal length of "(a-a^2)/4", or the other way around. Did I screw up?

Couldn't get the last one out.
Me and my friend got a/4.

eating

Wannabe COMP god
Me and my friend got a/4.
Ah crap. That means I probably got the parabola locus proof incorrect too.

calamebe

Active Member
Ah crap. That means I probably got the parabola locus proof incorrect too.
Well, your answer for iii) might just count as a carry on error, so I'm guessing you'd get the mark.

MorrisTheHorris

New Member
For the integral by substitution on 11b, I got the correct primitive + C and subbed back in for u but then got cheeky and tried to factorise out (x-4)^3/2, and left out a factor of 1/3 on the second term, do you reckon they'll just stop once they see I have the right answer and award me 3/3 or mark me down to 2/3 for the error?

Commando007

Member
Did few questions

1. D
2. B
3. A
4. C
5. A
6. D
Hope the rest are correct

For 11b I got
[(2/5)(x-4)^5/2]+[(8/3)(x-4)^3/2]+C

11e
x<-3 or -5/2 < x < 1/2

Hope they're correct

eating

Wannabe COMP god
Well, your answer for iii) might just count as a carry on error, so I'm guessing you'd get the mark.
I hope so. It's got the working down, so the method is clear. But 1 mark questions are hit-or-miss.

If I scrape into E4, I'll be very happy.

InteGrand

Well-Known Member
I got, for the question before, a focal length of "(a-a^2)/4", or the other way around. Did I screw up?

Couldn't get the last one out.
We should always check our answers to see if they are reasonable. Note that (a – a^2)/4 is going to be negative a lot of the time (e.g. if a = 2). But "a" was certainly allowed to be any positive number, so we'd be getting a negative focal length, a problem. (And it's pretty clear that the parabola for R should be upwards-facing when the main parabola is upwards facing, so it's not like we should be getting a negative answer to signify a downward parabola or anything like that.)

So in other words, our answer should certainly be something that's non-negative for all a > 0 (something like a/4 passes this test).

eating

Wannabe COMP god
Hope they're correct
Carrotsticks is going to post answers later on (look for his post earlier in the thread)

also FUCK FUCK I DID THE INTERNAL ANGLE NOT THE REFLEX ANGLE.

samcalamos

New Member
Carrotsticks is going to post answers later on (look for his post earlier in the thread)

also FUCK FUCK I DID THE INTERNAL ANGLE NOT THE REFLEX ANGLE.
Me too ((

Spoderman19

New Member
For the probability question in 11, did you need to evaluate it or is the binomial expression fine?

Ambility

Active Member
Carrotsticks is going to post answers later on (look for his post earlier in the thread)

also FUCK FUCK I DID THE INTERNAL ANGLE NOT THE REFLEX ANGLE.
Yeah I was so close to making that mistake... that's painful.

Ambility

Active Member
For the probability question in 11, did you need to evaluate it or is the binomial expression fine?
I think you would have needed to evaluate it.

hiimesh

New Member
This exam was not particularly difficult IMO. I had been getting 95% in the past exams but im looking at high 80s here. Stress rly got to me midway through the exam. It was just unusual that IMO the hardest questions were in the middle. I found the last question much too easy as well as the projectile. So I believe that many found this exam unsuual as there was no hard prijectile but some other bits were difficult, contrasting other years.

ANyone want to hazard what 60-61 raw out of 70 will get me in examination mark? i'd say 94-95