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Re: HSC 2013 2U Marathon Yeah but it doesn't explicitly state that D HAS to be in the first quadrant it just says find D such that ABCD forms a parallelogram. I remember questions like this in the past where students have got marks for 3 different solutions.

Re: HSC 2013 2U Marathon So is (-4, 1) still a solution?

Re: HSC 2013 2U Marathon Can't you just find difference of C from A, and apply that from B to D such that D(-4, 1)

Re: HSC 2013 2U Marathon \int_0^{\pi/4} 1 + \sin^2 x + \sin^4 x + \sin^6x + \dots \ dx \\ \\ \indent = \int_0^{\pi/4} \frac {1}{1-sin^{2}x} \ dx \\ \\ \indent = \int_0^{\pi/4} \frac {1}{cos^{2}x} \ dx \\ \\ \indent = \int_0^{\pi/4} sec^{2}x \ dx \\ \\ \indent = tan\frac {\pi}{4} - tan0 \\ \\...

Yes true! I've just learnt that way for some reason.

\int _{ 1 }^{ 4 }{ \frac { 1 }{ 3x } dx } = \frac { 1 }{ 3 } \int _{ 1 }^{ 4 }{ \frac { 3 }{ 3x } } dx \\ \\ \indent = \frac { 1 }{ 3 } (\log _{ e }{ 12 } -\log _{ e }{ 3 } ) \\ \\ \indent = \frac { 1 }{ 3 } \log _{ e }{ 4 }

Re: HSC 2013 2U Marathon \frac {1}{1-x} = 5x \\ \\ \indent 5x-5x^{2} = 1 \\ \\ \indent 5x^{2}-5x+1=0 \\ \\ \indent x = \frac {5 \pm \sqrt {(-5)^{2}-4(5)(1)}}{10} \\ \\ \indent x = \frac {5 \pm \sqrt {5}}{10}

Re: HSC 2013 2U Marathon x(49-x^2)^{1/2} \\ \\ \indent \frac {d}{dx} \quad x(49-x^{2})^{1/2} \\ \\ \indent = x \times -x(49-x^{2})^{-\frac {1}{2}} + (49-x^{2})^{1/2} \\ \\ \indent = \frac {-x^{2}}{\sqrt {49-x^{2}}} + \sqrt {49-x^{2}}

Yeah I didn't mean that :) was my solution correct though? Sent from my iPhone using Tapatalk 2

Re: HSC 2013 2U Marathon x^{2} - 6x -8y = 23 \\ \\ \indent (x-3)^{2} = 8y + 32 $ (Completing the square)$ \\ \\ \indent (x-3)^2 = 8(y+4) \\ \\ \indent \therefore $ Vertex at $(3, -4) \\ \\ \\ \indent 4a = 8 \\ \\ \indent a = 2 \\ \\ \indent \therefore $ Focus at $(3, -2). \\ \\ \indent...

Re: How many past papers have yous done ? Maths - like 6 maybe (not all completed, up to last question usually) Eco - 2 short answers, 1 MC Business - 1 short answers

Very hard paper, and 96%, that's impressive.

It'd be interesting to see who got first. :)

I'm not sure what sort of thing you're looking for for 6 marks, but I'd start with something like: 1. A computer input device has a number of operations. Most notably, it allows the user to interact and interface with the system. 2. Primary and secondary storage are two separate methods of...

I can't really remember covering data stream error checking either.

Re: HSC 2013 2U Marathon I'd write questions if I had the knowledge!

Re: HSC 2013 2U Marathon Yeah it was a pretty stupid mistake. :(

Re: HSC 2013 2U Marathon Woah that's heaps neat!

Re: HSC 2013 2U Marathon I'm not sure, all I know is 1/x integrated is ln(x), not sure about 1/ln(x).

Re: HSC 2013 2U Marathon I think this is right? \int \frac {1}{xln(x)} dx \\ \\ \indent = x \int \frac {\frac {1}{x}}{xln(x)} dx \\ \\ \indent = xln(xln(x)) + c