3 unit maths preliminary questionz marathon (1 Viewer)

bleakarcher · Jul 15, 2011

ill start off:

d/dx[x(ln(x))^2]

ohexploitable · Jul 15, 2011

we already have one

http://community.boredofstudies.org/showthread.php/243773-Preliminary-mathematics-marathon

SpiralFlex · Jul 15, 2011

bleakarcher said:
ill start off:

d/dx[x(ln(x))^2]

Via the product rule:

$\frac{dy}{dx}=1*(\ln x)^2 + \frac{2\ln x}{x} * x$

$\therefore \frac{dy}{dx}= (\ln x)^2 + 2\ln x$

bleakarcher · Jul 23, 2011

im bored letz get this going.

show that tan(15)=2-sqrt(3)

ohexploitable · Jul 23, 2011

ohexploitable said:
http://community.boredofstudies.org/showthread.php/243773-Preliminary-mathematics-marathon

also, double angle

SpiralFlex · Jul 23, 2011

$\tan30=\frac{2 \tan 15}{1-\tan^2 15}$

Form a quadratic and solve. I think Ohexploitable wants you to use his thread.

hscishard · Jul 23, 2011

^ spiral and exploitables method or tan(45-30)

hscishard · Jul 23, 2011

Ambiguous

bleakarcher · Jul 23, 2011

lol that would take much longer time.
i simply did this.
tan(15)=tan(45-30)
=[tan(45)-tan(30)]/[1+tan(45)tan(30)]
=[1-(1/sqrt(3))]/[1+(1/sqrt(3))]
simply and rationalise the denominator

hscishard · Jul 23, 2011

...

bleakarcher said:
ill start off:

d/dx[x(ln(x))^2]

That question

bleakarcher · Jul 23, 2011

wat about it? someone post the next question lol

ohexploitable · Jul 23, 2011

bleakarcher · Jul 23, 2011

gtfo lol

elliottjohnson · Jul 31, 2011

Solve:

2 < (3x+1)/(2x+4)

SpiralFlex · Jul 31, 2011

elliottjohnson said:
Solve:

2 < (3x+1)/(2x+4)

$\frac{3x+1}{2(x+2)} > 2$

$2(x+2)(3x+1) - 8(x+2)^2 > 0$

$2(x+2)[(3x+1)-4(x+2)]>0$

$2(x+2)(-x-7)>0$

$-2(x+2)(x+7)>0$

$-7<x<-2$

funnytomato · Aug 1, 2011

find the angle subtended by any of the side of a regular tetrahedron at its centre
(this probably won't appear in any of your exams... )

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3 unit maths preliminary questionz marathon (1 Viewer)

bleakarcher

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ohexploitable

hey

SpiralFlex

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bleakarcher

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ohexploitable

hey

SpiralFlex

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hscishard

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hscishard

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bleakarcher

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hscishard

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bleakarcher

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ohexploitable

hey

bleakarcher

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elliottjohnson

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SpiralFlex

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funnytomato

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