HSC 2013 Maths Marathon (archive) (2 Viewers)

[asianese]

Re: HSC 2013 2U Marathon

John likes boys and so will not get laid by either girl.

(ie negative probabilities)

 

[anthony_wheels]

Re: HSC 2013 2U Marathon

I'm curious - What other functions also satisfy the above 'restrictions' besides f(x) = lnx?

 

[RealiseNothing]

Re: HSC 2013 2U Marathon

I'm curious - What other functions also satisfy the above 'restrictions' besides f(x) = lnx?

is another from inspection

 

[spanky125]

Re: HSC 2013 2U Marathon

I'm curious - What other functions also satisfy the above 'restrictions' besides f(x) = lnx?

When:
A = 2
B = 2

 

[RealiseNothing]

Re: HSC 2013 2U Marathon

When:
A = 2
B = 2

wat

 

[Sy123]

Re: HSC 2013 2U Marathon

I'm curious - What other functions also satisfy the above 'restrictions' besides f(x) = lnx?

----

To find a proper functional solution we do:





Subbing in A=1



Integrating

 

[mahmoudali]

Re: HSC 2013 2U Marathon

I posted this in the general thread but it must have been to complex for their simple minds as I did not get a reply.

Sample Question:

John has the choice of either taking Stacey or Kristie to the prom.
The chance of Stacey putting it out is equivalent to x in the equation:
4x-3=8x+1
The chance of Kristie putting out is equivalent to y in the equation:
y+3=2-5y

Which girl should John take to the prom in order to have the greatest chance of getting laid?

no wonder you're in general maths

 

[Youi_]

Re: HSC 2013 2U Marathon

I posted this in the general thread but it must have been to complex for their simple minds as I did not get a reply.

Sample Question:

John has the choice of either taking Stacey or Kristie to the prom.
The chance of Stacey putting it out is equivalent to x in the equation:
4x-3=8x+1
The chance of Kristie putting out is equivalent to y in the equation:
y+3=2-5y

Which girl should John take to the prom in order to have the greatest chance of getting laid?

John should take spanky 125 for a 100% chance of getting laid

 

[spanky125]

Re: HSC 2013 2U Marathon

John should take spanky 125 for a 100% chance of getting laid

It wouldn't be rape, just a struggle snuggle.

 

[anthony_wheels]

Re: HSC 2013 2U Marathon

Hmmm... I agree with asianese "so trixxy". One question, is this some sort of geometric progression? Bit stumped lol

 

[integral95]

Re: HSC 2013 2U Marathon

Hmmm... I agree with asianese "so trixxy". One question, is this some sort of geometric progression? Bit stumped lol

add 1 and subtract 1

start by using limiting sum of 1+ cos+cos^2.....
and the same for 1+ sin + sin^2

this is allowed since the ratio sinx is between -1 and 1.
same for cos x.

 

[HeroicPandas]

Re: HSC 2013 2U Marathon

latex pls

Write it out again without brackets, group the sines together and then group cosines together

 

[JT145]

Re: HSC 2013 2U Marathon

I used simultaneous equations to find d, and from that , I got a.

that is so ObliviousNinja's handwriting

 

[anthony_wheels]

Re: HSC 2013 2U Marathon

how do you find inflexion pt properly? f''(x) = 0? i feel im missing a step..

Yeah, that's correct - then just use the table and test the values around the 'possible point of inflection' to confirm (or not to confirm) that it is a POI.
The reason why you need the table is because in some cases f''(x) may equal 0, but there is no POI. For example, f(x)=x^4, therefore, f''(x) = 12x^2. However, there is no POI with f(x) = x^4

 

[Menomaths]

Re: HSC 2013 2U Marathon

2 marks, show working.

 

[HeroicPandas]

Re: HSC 2013 2U Marathon

^That question is a challenge
Heres one to warm you up!

 

[Badsiii]

Re: HSC 2013 2U Marathon

2 marks, show working.

H=5

Area= 5/2(f(x1) +f(xn) + 2(f(x between))
Area= 5/2(2+0+2(4.5+5.1+3.6)= 71
C

 

[Menomaths]

Re: HSC 2013 2U Marathon

^That question is a challenge
Heres one to warm you up!

sin(2x) = 2sinx.cosx
sinx/2sinx.cosx
1/2cosx
1/2

 

[Badsiii]

Re: HSC 2013 2U Marathon

What is the domain and range for

Y=square root(9-x^2)

 

[Menomaths]

Re: HSC 2013 2U Marathon

What is the domain and range for

Y=square root(9-x^2)

Domain: -4 < x < 4
Range:All real y
??