Math Advanced Prediction/Thoughts (1 Viewer)

[Jerryclover]

As did I, but I'd like to check it again

sir, if you don't mind. Can you post your solutions to this problem(q33d)?

 

[Jerryclover]

what wait, i just differentiated it to find max turning point lol

I think that's the long way to do it... Since it's a concave down parabola, it will only have one maximum point which is the vertex..

 

[CopperPike]

No. The +100 in the equation y(t) accounts for that. But this question is fk'd up for advanced honestly, it's more of an ext1 question

Ah yes makes sense when I look at the eqn lol. That's a sneaky one I guess

 

[CopperPike]

Raw mean mark for last year's exam was 38.1/50 and scaled was 28.4/50. I wonder how our cohort's stats will look like .

 

[Jerryclover]

oh i didnt see that, i was more so wondering why u thought it was difficult for adv

ah, ok. I was more so referring to the entirety of q26. If i hadn't doen extension 1, i would never make the connection to substiute y(t)= 0 for 26b. This is very similar to ext1 projectile motion questions, so yeah

 

[CM_Tutor]

sir, if you don't mind. Can you post your solutions to this problem(q33d)?

​

...using the -score of +2 (above the middle 95%) to mean top 2.5% and that 80% of them solve in under 2 h

 

[Jerryclover]

​

...using the -score of +2 (above the middle 95%) to mean top 2.5% and that 80% of them solve in under 2 h

Thanks for this

 

[5uckerberg]

I know some of the solutions are wrong in this pdf I agree with CM_Tutor and Trebla.

View attachment 33772

I don't know if this was mentioned previously...but as the question asks for height above ground level, shouldn't the answer be 445m (so 345+100 above ground level)?

I find the second part is extremely questionable. I mean can you remove a factor of 5 from the question?

 

[5uckerberg]

could you check q25?

Q25's solution is very messed up. I mean what were they thinking.

 

[CopperPike]

Honest estimation, a 77-81 raw will amount to an 89-92 scaled this year. Last year the examination wasn't too bad, with the exception of the cricket question (which wasn't even bad at all). 2021, comparatively, will have a greater spread of results and a smaller percentage of those in the top 1-0.001%. The raw mean mark will be a lot lower.

Hopefully… we will have to wait and see.Yeah the 2020 was quite a breeze. 2013 wasn’t that bad at all, and 75 was scaled to a band 6. I reckon the cutoff will probs be 73 (maybe) but more close to 74-75 imo

 

[stressedadfff]

Raw mean mark for last year's exam was 38.1/50 and scaled was 28.4/50. I wonder how our cohort's stats will look like .

thats horrid

 

[stressedessert04]

Honest estimation, a 77-81 raw will amount to an 89-92 scaled this year. Last year the examination wasn't too bad, with the exception of the cricket question (which wasn't even bad at all). 2021, comparatively, will have a greater spread of results and a smaller percentage of those in the top 1-0.001%. The raw mean mark will be a lot lower.

praying u r right

 

[CM_Tutor]

Q25's solution is very messed up. I mean what were they thinking.

Q25 is the exact sort of mistake that everyone should be checking for after each answer by asking yourself "is my answer reasonable?" As several people have noted, turning $8,000 into over $60,000 in 8 years at less than 1% interest pa = unreasonable. Just like the normal distribution / number of babies question, where the given answer is also obviously unreasonable.

 

[CM_Tutor]

I know some of the solutions are wrong in this pdf I agree with CM_Tutor and Trebla.

I find the second part is extremely questionable. I mean can you remove a factor of 5 from the question?

Is it just mean, or is the arithmetic in 26(b) wrong? isn't it ?

 

[5uckerberg]

Is it just mean, or is the arithmetic in 26(b) wrong? isn't it ?

I find it leans to as the answer I was talking about part b.

 

[CM_Tutor]

Oops, I'm wrong... I read their working for the time as



but I have misread and it is actually

 

[Johnny Sins]

despite the paper being difficult, i reckon a raw for a b6 will be in the low 80s high 70s

 

[5uckerberg]

Oops, I'm wrong... I read their working for the time as



but I have misread and it is actually

Then by default, it has to be for the velocity as the particle reaches the ground noting that the negative represents slowing down.

 

[CM_Tutor]

Then by default, it has to be for the velocity as the particle reaches the ground noting that the negative represents slowing down.

Yes and No.

The velocity at impact with the ground is indeed or in a downwards direction. The particle is not slowing down, however, it is speeding up as it is accelerating in the negative direction and moving in the negative direction.

Note, also, that while this is an example of projectile motion, the particle has been projected vertically and so all of the motion is occurring in one dimension, as is typical in Advanced Maths motion questions. What makes it unusual is that motion is all vertical rather than all horizontal along an -axis.

 

[RaymondB]

Guys for the second short answer I used tan instead of cos, what is wrong with me (also how many lost marks is that, will I at least get maybe 2 pity marks pls cause I did the right working out, wrong trig identity)