Carrotsticks' MX2 HSC 2013 Solutions (3 Viewers)

[Makematics]

guys i have a question. for the 4 mark volumes, i never like to 'unroll' the shell into a rectangular prism. instead i like to derive the result from fresh using subtraction of the inner and outer radii. when applying this method today, i forgot the height of the shell, and as a result there was no e^x present in my integral AT ALL. how many marks will i lose for it? it's an absolutely terrible mistake, i know...

 

[RivalryofTroll]

yep. first i did it in my trial, and again today. fk. it's always Q11.


i think this year's exam was very unique, in that it really favoured the top students, which is why you see people going on about how "half of the ruse and nsb cohort got 100" (im exaggerating, relax). at the same time it really punished rote learners, like the inequality question in Q16 was really quite standard yet it stumped a fair few people.

Some of the questions favoured rote-learners though (but then again everyone is on equal playing field for such questions) .

As a 'rote-learner'for 4U, I can understand what you're saying though.

I feel that most people either SCREWED UP HARD or RIPPED IT HARD.

Not so many people in between the two spectrum.

 

[anomalousdecay]

yep. first i did it in my trial, and again today. fk. it's always Q11.


i think this year's exam was very unique, in that it really favoured the top students, which is why you see people going on about how "half of the ruse and nsb cohort got 100" (im exaggerating, relax). at the same time it really punished rote learners, like the inequality question in Q16 was really quite standard yet it stumped a fair few people.

Couldn't of said it better. Explains why I failed geo. I made a silly in the inequality though.

Reading your statement, I think there will be a large gap between the e3 and e4 cut-offs.

 

[RivalryofTroll]

guys i have a question. for the 4 mark volumes, i never like to 'unroll' the shell into a rectangular prism. instead i like to derive the result from fresh using subtraction of the inner and outer radii. when applying this method today, i forgot the height of the shell, and as a result there was no e^x present in my integral AT ALL. how many marks will i lose for it? it's an absolutely terrible mistake, i know...

Not too sure if you can get marks even.... but then again I'm not sure.

 

[obliviousninja]

I'm wondering how many people in the state for question 5 of the multiple choice mistook as

I know my friend did.

I was so close in doing that. then I looked at all the other rand graphs which u never see. then I relooked at the question. thank God I got it right or else I woulda gotten 0/10

 

[panda15]

guys i have a question. for the 4 mark volumes, i never like to 'unroll' the shell into a rectangular prism. instead i like to derive the result from fresh using subtraction of the inner and outer radii. when applying this method today, i forgot the height of the shell, and as a result there was no e^x present in my integral AT ALL. how many marks will i lose for it? it's an absolutely terrible mistake, i know...

2-3 tbh. The e^x was the main part of the question, and lead on to integration by parts etc. I tried it the same way you did, but when I realised there was no e^x in my equation I resorted back to shells.

 

[obliviousninja]

FK another mistake in volumes :'( will most likely cost me two marks

ur mark is linearly decreasing each hour.

 

[anomalousdecay]

guys i have a question. for the 4 mark volumes, i never like to 'unroll' the shell into a rectangular prism. instead i like to derive the result from fresh using subtraction of the inner and outer radii. when applying this method today, i forgot the height of the shell, and as a result there was no e^x present in my integral AT ALL. how many marks will i lose for it? it's an absolutely terrible mistake, i know...

I had two drawings, one unrolled and one of the graph and the derivation of the limits.
My method is actually somewhat shells and slices put together lol.

Probably two marks. One mark was probably for using Interrogation by parts and one for the height.
But I'm guessing you already cleared the e4 cut-off anyway .

 

[Makematics]

Not too sure if you can get marks even.... but then again I'm not sure.

dudeee i will get some marks haha, definitely for at least getting an expression and integrating it.

 

[Makematics]

2-3 tbh. The e^x was the main part of the question, and lead on to integration by parts etc. I tried it the same way you did, but when I realised there was no e^x in my equation I resorted back to shells.

no i did use shells. its just i have a different way of doing shells that led me to make the mistake :/
i did draw a graph and a shell though

 

[RivalryofTroll]

dudeee i will get some marks haha, definitely for at least getting an expression and integrating it.

1-2 marks then if you're so confident

(Well, you do know what you're doing unlike me - who just mindlessly uses cylindrical shells to get it out)

How'd the rest of your school do?

 

[obliviousninja]

1-2 marks then if you're so confident

(Well, you do know what you're doing unlike me - who just mindlessly uses cylindrical shells to get it out)

How'd the rest of your school do?

omg RoT, ur aliveeeeeeeeee. where have u been. snaking it away from bos for past week?

 

[Makematics]

1-2 marks then if you're so confident

(Well, you do know what you're doing unlike me - who just mindlessly uses cylindrical shells to get it out)

How'd the rest of your school do?

well im pretty sure i can get a mark or two. umm idk, i guess we did alright, some people bombed out unexpectedly apparently. i thought the hsc was similar to our trial though since the earlier questions were hard but the last question was not so hard.

 

[Locus]

For q12 dii)
Did we just have to show that P was the midpoint of AB to show O lies on the circle? did we have to give reasoning or something that PA and PB were equal radii?

 

[RivalryofTroll]

omg RoT, ur aliveeeeeeeeee. where have u been. snaking it away from bos for past week?

I was doing 4U past papers (did 6 in 2 days). And it ended up being a waste of time cause HSC slayed me.

well im pretty sure i can get a mark or two. umm idk, i guess we did alright, some people bombed out unexpectedly apparently. i thought the hsc was similar to our trial though since the earlier questions were hard but the last question was not so hard.

You'll be fine son.

Bombed out as in complete under 50 devastation lol or is like 60s considered bombing out to you?

My school seems to have fucked up --> everyone on BoS = so ezy, heaps of peeps at my school = dat was hard.

Also, 2nd internally at my school said he's expecting high 90s raw yet 1st internally is expecting high 80s raw lol...

 

[panda15]

no i did use shells. its just i have a different way of doing shells that led me to make the mistake :/
i did draw a graph and a shell though

Ahh. When you said inner and outer radius, I just thought of the washer method.

 

[Makematics]

I was doing 4U past papers (did 6 in 2 days). And it ended up being a waste of time cause HSC slayed me.



You'll be fine son.

Bombed out as in complete under 50 devastation lol or is like 60s considered bombing out to you?

My school seems to have fucked up --> everyone on BoS = so ezy, heaps of peeps at my school = dat was hard.

Also, 2nd internally at my school said he's expecting high 90s raw yet 1st internally is expecting high 80s raw lol...

i reckon i'll lose one mark for making the mistake of missing the cylinder's height, and one mark for making the integration too simple by missing the e^x.
idk, some of the people i talked to say that they got a lot lower than what they would usually get, so not sure. some did quite well. not too sure about top students tbh.



and im too scared to check my answers with carrot's solutions in case i find more sillies

 

[RealiseNothing]

For q12 dii)
Did we just have to show that P was the midpoint of AB to show O lies on the circle? did we have to give reasoning or something that PA and PB were equal radii?

You had to also state that angle AOB was a right angle.

 

[RealiseNothing]

guys i have a question. for the 4 mark volumes, i never like to 'unroll' the shell into a rectangular prism. instead i like to derive the result from fresh using subtraction of the inner and outer radii. when applying this method today, i forgot the height of the shell, and as a result there was no e^x present in my integral AT ALL. how many marks will i lose for it? it's an absolutely terrible mistake, i know...

1-2 marks

 

[Makematics]

terry lee still hasnt uploaded solutions. i think he gave up after seeing that his place has been taken by carrot as the releaser of quick solutions.