HSC 2016 Maths Marathon (archive) (1 Viewer)

[Drsoccerball]

Re: HSC 2016 2U Marathon

what day was it specifically lol

It's whenever 2 unit kids learn the rule hahahah

 

[InteGrand]

Re: HSC 2016 2U Marathon

I think it's time to explain the burning lady rule. So what happened is on that day we had assembly and there were these dancing people. Just as the show opens the lady puts a ball of flames into her mouth and she screws up and it catches her face on fire... So she was alright afterwards but ojn that day we learnt that rule. And it made sense to call it the burning lady rule as the ladies standing and then she falls because shes on fire to put it out.

When she's standing.

When she fell.

And the broken pippet rule happened on the same day that the next year learnt that rule so we can predict the time each year something bad's going to happen lol...

So were these terms ("burning lady log rule" and "broken pipette rule") basically made up by you and your friends? (I can't see the connection between that log law and those terms haha.)

 

[Nailgun]

Re: HSC 2016 2U Marathon

Oh jokes, as in on the day that the grade learnt the rule lol
Fun times

 

[Nailgun]

Re: HSC 2016 2U Marathon

When she's standing.
When she fell.

imo her head fell off

 

[Drsoccerball]

Re: HSC 2016 2U Marathon

So we're these terms ("burning lady log rule" and "broken pipette rule") basically made up by you and your friends? (I can't see the connection between that log law and those terms haha.)

Yeah our maths teacher always referred to that rule as the burning lady rule after that point.

 

[davidgoes4wce]

Re: HSC 2016 2U Marathon



Not sure how to do this one, answer is 1.0921 radians. A bit thrown off by the wording of ' show the cross section of a trough of length 5m'

 

[leehuan]

Re: HSC 2016 2U Marathon

Not sure how to do this one, answer is 1.0921 radians. A bit thrown off by the wording of ' show the cross section of a trough of length 5m'

Volume = Area * some length
= h/2(a+b) * 5

A CROSS SECTION, is when you slice a part of the shape, view it from any appropriate view (in this case front view), and draw the 2D version of the FRONT view.

 

[davidgoes4wce]

Re: HSC 2016 2U Marathon

Volume = Area * some length
= h/2(a+b) * 5

A CROSS SECTION, is when you slice a part of the shape, view it from any appropriate view (in this case front view), and draw the 2D version of the FRONT view.

Still cant get the answer Im getting a different radian value

 

[davidgoes4wce]

Re: HSC 2016 2U Marathon

Forget about it, I got the answer. My excuse is, I went overseas for a month and Im rusty.

 

[davidgoes4wce]

Re: HSC 2016 2U Marathon

Here is the full working out:

 

[davidgoes4wce]

Re: HSC 2016 2U Marathon



Need a kick start on a) and b). Had a few problems deriving the formula.

 

[wu345]

Re: HSC 2016 2U Marathon

Part a:
Let R=cone radius, h=cone height, r=sphere radius


sorry im missing pi in the last two lines

Part b:
Let s=slant height of cone

 

[Nailgun]

Re: HSC 2016 2U Marathon

Part a:
Let R=cone radius, h=cone height, r=sphere radius
View attachment 32862

sorry im missing pi in the last two lines

Part b:
Let s=slant height of cone
View attachment 32863

btw If you're using daum just copy/paste into

 

[wu345]

Re: HSC 2016 2U Marathon

thanks for the tip! sorry for not including a diagram earlier-hopefully this makes it clear
(angle subtended at centre double angle subtended at circumference from circle geo)


Also: my bad i used 3u identities to transform sin2x - you can do it with cosine rule and simple trig

 

[Nailgun]

Re: HSC 2016 2U Marathon

thanks for the tip! sorry for not including a diagram earlier-hopefully this makes it clear
(angle subtended at centre double angle subtended at circumference from circle geo)
View attachment 32864

Also: my bad i used 3u identities to transform sin2x - is this question from a 3u or 2u textbook?

Ohh okay, is the circle geo 3u as well?
Spent like 30 mins on this yesterday lol, figured I was doing something wrong

 

[wu345]

Re: HSC 2016 2U Marathon

Ohh okay, is the circle geo 3u as well?
Spent like 30 mins on this yesterday lol, figured I was doing something wrong

nono you can do it without any 3u i just did a dumb way hahaha

edit: Wait nvm you need 3u identity to transform cos 2x if youre using cosine rule oops

 

[wu345]

Re: HSC 2016 2U Marathon

I thought basic circle geo was assumed knowledge but maybe your school didnt do it in year 10?

 

[Nailgun]

Re: HSC 2016 2U Marathon

idk maybe we did lol

i figured if the textbook goes through even like basic algebra, everything that could be tested would be in it lol

 

[wu345]

Re: HSC 2016 2U Marathon

yeah just be wary of it - but anyways sorry for all the spam earlier, i found a way to do it without any 3u will post soon

 

[leehuan]

Re: HSC 2016 2U Marathon

I thought basic circle geo was assumed knowledge but maybe your school didnt do it in year 10?

Circle geometry is not assumed knowledge for mathematics 2 unit as the three LOBES of 10 5.3 are ONLY RECOMMENDED for those who intended to take Extension 1 mathematics.

Those that do 5.3 withOUT the LOBES are highly recommended to have sticked with 2 unit to begin with.
The LOBES were recommended for those that specifically wanted to do 3 unit.