HSC 2012 MX1 Marathon #1 (archive) (1 Viewer)

[Examine]

Re: 2012 HSC MX1 Marathon

Given that tanx=3, where x is acute, find the values of
(i) Cosx

How do you start/ set out this question.

 

[nightweaver066]

Re: 2012 HSC MX1 Marathon

Given that tanx=3, where x is acute, find the values of
(i) Cosx

How do you start/ set out this question.

 

[RivalryofTroll]

Re: 2012 HSC MX1 Marathon

Given that tanx=3, where x is acute, find the values of
(i) Cosx

How do you start/ set out this question.

tan x = 3
sinx/cosx = 3
sin^2x/cos^2x = 9
1-cos^2x/cos^2x = 9
1-cos^2x = 9cos^2x
10cos^2x = 1
cos^2x = 1/10
cosx = Yeah!

I think this is right?
cosx = Square root (1/10)

 

[RivalryofTroll]

Re: 2012 HSC MX1 Marathon

DAM! Beat me to it!

 

[Carrotsticks]

Re: 2012 HSC MX1 Marathon

If I had the money, I would personally buy everybody who posts in this thread a graphics tablet.

 

[IamBread]

Re: 2012 HSC MX1 Marathon

If I had the money, I would personally buy everybody who posts in this thread a graphics tablet.

Haha would come in handy.

 

[Examine]

Re: 2012 HSC MX1 Marathon

If I survive maths extension 1 by the HSC I will thank you guys so much. Not even thinking about extension 2 anymore lol

 

[Nooblet94]

Re: 2012 HSC MX1 Marathon

View attachment 24384

and tan=opp/adj, so you get the required result.


QUESTION:
Prove by induction that n lines in the plane (no two being parallel and no three concurrent) divide the plan into regions.

 

[Carrotsticks]

Re: 2012 HSC MX1 Marathon

If I survive maths extension 1 by the HSC I will thank you guys so much. Not even thinking about extension 2 anymore lol

Why not?

 

[AAEldar]

Re: 2012 HSC MX1 Marathon

If I survive maths extension 1 by the HSC I will thank you guys so much. Not even thinking about extension 2 anymore lol

That is an extremely poor attitude to have and you won't succeed with it.

Doing 4U helps immensely with your 3U skills, plus it's a lot more fun. It's still early days, plenty of time to improve.

 

[Examine]

Re: 2012 HSC MX1 Marathon

I've realised compared to everybody else my mathematics skill is nothing.

 

[Nooblet94]

Re: 2012 HSC MX1 Marathon

That is an extremely poor attitude to have and you won't succeed with it.

Doing 4U helps immensely with your 3U skills, plus it's a lot more fun. It's still early days, plenty of time to improve.

Not to mention it means that 3U counts for 2 units.

I've realised compared to everybody else my mathematics skill is nothing.

Compared to the people on this forum it might not be. Yet. The "maths people" here are pretty elite. You've got people in their first/second year of university maths, people who've competed in the international maths olympiad, Spiral and (iirc) someone that's about to start a Phd in maths in the US. They've had much, much more experience in maths than most people, so it's not really fair on you to compare yourself to them. I often feel intimdated by their far superior abilities, and I'm pretty sure lots of other people on this forum do as well.

 

[Examine]

Re: 2012 HSC MX1 Marathon

Ehh I guess I'll just keep on trucking and see the end result.

 

[nightweaver066]

Re: 2012 HSC MX1 Marathon

I've realised compared to everybody else my mathematics skill is nothing.

You should also realise that we're all in year 12 and there's the occasional university student posting in here.

 

[Examine]

Re: 2012 HSC MX1 Marathon

You should also realise that we're all in year 12 and there's the occasional university student posting in here.

Hmm I guess so, though with some questions I just look at them and think "WTF DOES THIS EVEN MEAN?"

 

[AAEldar]

Re: 2012 HSC MX1 Marathon

Hmm I guess so, though with some questions I just look at them and think "WTF DOES THIS EVEN MEAN?"

I was like that at the start of Year 11 when I was using the forums. Ohexploitable and hscishard, among others, knew a lot more maths than I did because they'd studied ahead and all that yet I'd only done what the class had done. It took a long time before I was finally able to understand all the questions that were asked - got to be patient.

 

[Examine]

Re: 2012 HSC MX1 Marathon

2Cos(360-48) = 2cos48 which = cos(180-48) right/wrong?

 

[RivalryofTroll]

Re: 2012 HSC MX1 Marathon

Hmm I guess so, though with some questions I just look at them and think "WTF DOES THIS EVEN MEAN?"

:/ Don't worry I feel the same too!
Everything looks hard now but when you do it then yeah, everything becomes clear!

 

[Nooblet94]

Re: 2012 HSC MX1 Marathon

2Cos(360-48) = 2cos48 right/wrong?

right.

 

[RivalryofTroll]

Re: 2012 HSC MX1 Marathon

2Cos(360-48) = 2cos48 which = cos(180-48) right/wrong?

cos(360-x) = cosx
cos(180-x) =-cosx
So... yeah....