Discussion and Suggested Solutions - Mathematics 2017

[jamonwindeyer]

Just adding on, conceptually wouldn't a limiting sum = 2 be approaching 2 when the number of terms approach infinite instead of being exactly equal to 2? (in the case of r = 0 and a = 2)

Hmm now that is a really good point - Okay, yeah, I'm strongly leaning that way mathematically now. I'm still skeptical whether NESA will mandate that you spot it - What I'll do is add it in red with a note that it might not be necessary for full marks, and I guess we'll keep fingers crossed! I hope they give it to the people who just put \(0<a<4\), would be nice to have more marks given out

[Anything]

Hmm now that is a really good point - Okay, yeah, I'm strongly leaning that way mathematically now. I'm still skeptical whether NESA will mandate that you spot it - What I'll do is add it in red with a note that it might not be necessary for full marks, and I guess we'll keep fingers crossed! I hope they give it to the people who just put \(0<a<4\), would be nice to have more marks given out

I didn't get it right in the exam, but i'm glad I could contribute to the discussion
 

[adelaidecruz]

Hi! Does anyone have any predictions on this year's B5 cutoff?

[Anything]

Hi! Does anyone have any predictions on this year's B5 cutoff?

I believe Jamon mentioned mid to high 70's. Alternatively you can check out this link http://rawmarks.info/wiki/Mathematics. If you want to compare past years and make your own judgement.

[jamonwindeyer]

I didn't get it right in the exam, but i'm glad I could contribute to the discussion

Really appreciate it! Fingers crossed you get the marks regardless

I believe Jamon mentioned mid to high 70's. Alternatively you can check out this link http://rawmarks.info/wiki/Mathematics. If you want to compare past years and make your own judgement.

I think 2013 in that database would be a good recent reference

[Merin Thomas]

Hey asking for a friend XD Wondering what the highest in 2013 was? And also, is it fine to do transversals ratio for question 16? 
Thanks for the help (:

[mfield]

do you think a raw mark of 82 would be a band 6 for this paper. Personally found it difficult

[jamonwindeyer]

Hey asking for a friend XD Wondering what the highest in 2013 was? And also, is it fine to do transversals ratio for question 16? 
Thanks for the help (:

What do you mean by highest, like, highest mark? Probably still 100% but not sure!

And yep, transversals was fine and almost definitely faster than my method

do you think a raw mark of 82 would be a band 6 for this paper. Personally found it difficult

Can't know for sure obviously but my thinking is that it would align to a 90 or above

[georgiia]

Hmm now that is a really good point - Okay, yeah, I'm strongly leaning that way mathematically now. I'm still skeptical whether NESA will mandate that you spot it - What I'll do is add it in red with a note that it might not be necessary for full marks, and I guess we'll keep fingers crossed! I hope they give it to the people who just put \(0<a<4\), would be nice to have more marks given out

Thats sort of what i did. I showed that |r| < 1 and then said as r approaches -1 a approached 0 ect. but didn't write it like 0<r<4
Will I still get the marks?
(is subbed in -.9 and .9 to show this)

Also for the very last part of the last question, i messily proved that it bisected the angles but algebraically with pro numerals. Can that still get me the marks if i did it correctly? Thanks

[Livchum]

Hi Jamon!

Do you think between late 60s to mid 75 could potentially fall as a band 5?

Thanks.

[jamonwindeyer]

Thats sort of what i did. I showed that |r| < 1 and then said as r approaches -1 a approached 0 ect. but didn't write it like 0<r<4
Will I still get the marks?
(is subbed in -.9 and .9 to show this)

Also for the very last part of the last question, i messily proved that it bisected the angles but algebraically with pro numerals. Can that still get me the marks if i did it correctly? Thanks

The substitution of values near 1 and -1 might not get you full marks but it isn't as rigorous, but you'll get 2/3 I'd say!

Yep, algebraic approach to that last question is fine provided it is correct

Hi Jamon!

Do you think between late 60s to mid 75 could potentially fall as a band 5?

Thanks.

I think that is definitely possible, probably low 70's but maybe lower, we'll have to see

[georgiia]

The substitution of values near 1 and -1 might not get you full marks but it isn't as rigorous, but you'll get 2/3 I'd say!

Yep, algebraic approach to that last question is fine provided it is correct

Thanks

[engido244]

I'm looking at a raw mark of between 85-89 depending on how hard I'm marked and I'm 2/14 in the cohort. But 1st and 2nd are quite close and then there's a huge drop off. Do you guys think I could still slide/align into a band 6?

[Livchum]

I think that is definitely possible, probably low 70's but maybe lower, we'll have to see

Thank you! So seeing as I have calculated my raw mark to be around the 70-71 mark, this could potentially be a band 5?

[TheSpicyMeatBall]

in question 14 ciii you reckon you should have used the rounded of value for k as that gives you a value of 880 years while using the complete value of k gives you 870 years
do you think both answers may end up being valid