Mathematics Predictions/Thoughts (4 Viewers)

[Hscbuzman]

For the rate of change question, are we meant to have the negative in the answer like -365 leaves/day. I wrote decreasing at a rate of 365 leaves/day

Thats minus one mark

 

[StudyOnly]

For the rate of change question, are we meant to have the negative in the answer like -365 leaves/day. I wrote decreasing at a rate of 365 leaves/day

no it's not minus one mark. I'd assume that would be fine... especially since it shows it is decreasing...

 

[abdulrahmanbhatti02]

no it's not minus one mark. I'd assume that would be fine... especially since it shows it is decreasing...

Yeah, I doubt they'd deduct a mark for that. Besides, rates are usually positive

 

[abdulrahmanbhatti02]

no it's not minus one mark. I'd assume that would be fine... especially since it shows it is decreasing...

Did you write -365 leaves / day or as I did? Some others in my class also wrote 'Decreasing at a rate of 365 leaves/day'

 

[Saturday]

Here are my answers to question 15.

 

[flowerp]

For the rate of change question, are we meant to have the negative in the answer like -365 leaves/day. I wrote decreasing at a rate of 365 leaves/day

That is correct - both decreasing at 365 etc. And rate of change=-365 etc are right. You only lose marks if you use a double negative, ie write decreasing at -365

 

[captain stones]

What was the answer for q10 MC

A

 

[StudyOnly]

A

I got C

 

[captain stones]

Do you think band 6 might be a bit lower. Our paper was pretty on par with 2013 I think

i think 2013 is the hardest in last 8 or 9 yrs, like way harder than this yr

 

[StudyOnly]

Here are my answers to question 15.

NOOOOOO, I forgot to discard the negative 2 for the log question!!!

 

[alussovsky]

for the national park question part ii, i completely missed out on the whole D^2 part of "show that x=2 is a minimum for D^2" aNd fREAKING DIFFERENTIATED D RATHER THAN D^2. i wanted to punch myself after i wrote "x=2 is a minimum for D, therefore it is a minimum for D^2"

 

[flowerp]

NOOOOOO, I forgot to discard the negative 2 for the log question!!!

OMG SAME ! I used the rule e^lna = a instead of logging etc !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[_rakelt]

NOOOOOO, I forgot to discard the negative 2 for the log question!!!

me 2 : (((((((( i added both ugh

 

[hello288292]

NOOOOOO, I forgot to discard the negative 2 for the log question!!!

OMG SAME ! I used the rule e^lna = a instead of logging etc !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Omg SAME I was so close to leaving it there but I when I was checking my answer, it gave a math error and I'm like crap I have to discard it

 

[Saturday]

I'm going to let the tutoring centres do Q14 and before, but (c) is probably the hardest question in 14, so here's one possible solution:

Triangle AFE is isosceles because AF = FE (regular hexagon). Angle sum of a hexagon = (n-2)180 = 4*180 = 720. Again, it's a regular hexagon so angle AFE = 720/6 = 120. Therefore angle FEA = (180 - 120)/2 = 30 (base angles of an isosceles triangle are equal). So angle AED = 120 - 30 = 90 (adjacent angles). Therefore angle XED = 90 as well (adjacent angles on a straight line). So XED is a right triangle.

That means we can use right angle trig in XED. tan(angle DXE) = DE/EX = 1/EX. But also, angle DXE = angle FAE (alternate angles, AF || CX due to the symmetry of the regular hexagon). And angle FAE = 30 degrees (it's the other base angle of the isosceles triangle AFE). So tan30 = 1/EX; that is, 1/sqrt(3) = 1/EX. So EX = sqrt(3).

 

[abdulrahmanbhatti02]

That is correct - both decreasing at 365 etc. And rate of change=-365 etc are right. You only lose marks if you use a double negative, ie write decreasing at -365

Yep! I confirmed this with a teacher who marks the HSC and he said both would receive the full mark

 

[Saturday]

I would have probably skipped 14(c) if I was sitting the exam and come back to it at the end... it took me a lot of time to come up with that solution! And this is coming from someone who got 100% in his HSC for Maths Extension 1.

 

[anerd]

I would have probably skipped 14(c) if I was sitting the exam and come back to it at the end... it took me a lot of time to come up with that solution! And this is coming from someone who got 100% in his HSC for Maths Extension 1.

Can you please do MCQ?

 

[abdulrahmanbhatti02]

I would have probably skipped 14(c) if I was sitting the exam and come back to it at the end... it took me a lot of time to come up with that solution! And this is coming from someone who got 100% in his HSC for Maths Extension 1.

This is how I did it (attached). It was definitely tricky but I stared at it during reading time and it somehow clicked

 

[Saturday]

I think these are the answers to the MCQ. I thought they were kind of tricky for a 2U paper. Sorry, no working:

1. B
2. D
3. B
4. C
5. A
6. C
7. D
8. C
9. A
10. B