Re: Maths- Gym for Brainiacs

by urbaNRoots Mon Sep 10, 2012 11:58 pm

Arghh!!!!

Ok I did this shit again Laughing

and it got me k=-1/2. If I'm wrong I'm not doing it again Mad

Maths- Gym for Brainiacs - Page 25 34hwcpk

by Babun Tue Sep 11, 2012 12:24 am

Why do you guess k? eco smile

Equal what you calculated to 2/3. Let me see:

(4+4k)/ ( 3* sqrt( 1+k)^3) = 2/3
4*(1+k)/( 3* sqrt( 1+k)^3) = 2/3
4*(1+k)/ ( 3*(1+k)*sqrt(1+k)) = 2/3 and so on... You almost solved the shit eco smile

by urbaNRoots Tue Sep 11, 2012 12:46 am

k=+-sqrt(2)-1

Finally Laughing

did the integral but struggled to solve k Laughing

by RealGunner Tue Sep 11, 2012 1:04 am

kiranr wrote:Yeah, i did that and integrated over the interval.

The interval is -1/(k+1)^(1/2) to +1/(k+1)^(1/2)

But the integral of g(x) minus integral of f(x) over the interval gets very complicated to solve for k.

I only tried it once and then decided to assume it is ellipse. I may be making some mistake. I will try again when i get the time, but if you solve it before, tell us the answer.

That's exactly what i did, However It's integral over integral in the end and i don't think it will end pretty. Although it might be a case of f'(x)/g(x)

by Babun Tue Sep 11, 2012 1:06 am

German highschool Maths- Gym for Brainiacs - Page 25 754a9adc_jackie-chan-meme_reasonably_small

Babun wrote:Why do you guess k? Equal what you calculated to 2/3. Let me see:

(4+4k)/ ( 3* sqrt( 1+k)^3) = 2/3
4*(1+k)/( 3* sqrt( 1+k)^3) = 2/3
4*(1+k)/ ( 3*(1+k)*sqrt(1+k)) = 2/3 and so on... You almost solved the shit

Let's continue at home. According to urbanroot's prior calculation:
(4+4k)/ ( 3* sqrt( 1+k)^3) = 2/3
4*(1+k)/( 3* sqrt( 1+k)^3) = 2/3
4*(1+k)/ ( 3*(1+k)*sqrt(1+k)) = 2/3 ,eradicate (1+k) from the fraction on the left

=> 4/(3*sqrt(1+k)) = 2/3 | divide both sides by 2/3
=> 2/ sqrt(1+k) = 1 | ( )²
=> 4/ (1+k) = 1² <=> 1+k= 4 => k=3

I don't know whether the answer is right or wrong but k=3 according to urban's prior calculations.

urbaNRoots wrote:k=+-sqrt(2)-1

Finally did the integral but struggled to solve k

Are you a highschooler? eco smile

by RealGunner Tue Sep 11, 2012 1:15 am

Wtf is that School teaching their kids lmao

by Babun Tue Sep 11, 2012 1:21 am

RealGunner wrote:Wtf is that School teaching their kids lmao

She said it's from their exercise book Laughing

I asked her to post a photo of that book eco smile

by spanky Tue Sep 11, 2012 1:23 am

i can see that u guys need the spanksters help Very Happy

by RealGunner Tue Sep 11, 2012 1:26 am

And i was planning to do my masters in Germany Laughing

sack that now lol

by Babun Tue Sep 11, 2012 1:29 am

RealGunner wrote:And i was planning to do my masters in Germany sack that now lol

Masters in what? eco smile

spanky489 wrote:i can see that u guys need the spanksters help

Spanky

Verify please whether k=3 is the correct answer Laughing

by RealGunner Tue Sep 11, 2012 1:30 am

Software Engineering with Games Concept

by urbaNRoots Tue Sep 11, 2012 1:31 am

Babun wrote:Are you a highschooler?

I study computer engineering, tried to solve this as I remembered the formula but got caught eco smile

by Babun Tue Sep 11, 2012 1:31 am

RealGunner wrote:Software Engineering with Games Concept

You could give it a try Laughing

Ask Urban, he studies something smiliar to software engineering in Germany I guess eco smile

by kiranr Tue Sep 11, 2012 1:39 am

RealGunner wrote:

That's exactly what i did, However It's integral over integral in the end and i don't think it will end pretty. Although it might be a case of f'(x)/g(x)

Integral over integral RG?

I just got k = 8 now Laughing

After intergration, it would be x - (k*x^3)/3 - (x^3)/3. Then you sub 1/root(k+1) and -1/root(k+1) into this and equate to 2/3.

so it will be

x ( 1 - ((x^2)/3)(k+1)) over which you sub +1/root(k+1) to -1/root(k+1).

When you sub this, you get 2/root(k+1) = 2/3. Hence k = 8.

Please check it guys.

by Babun Tue Sep 11, 2012 1:42 am

kiranr wrote:
RealGunner wrote:

That's exactly what i did, However It's integral over integral in the end and i don't think it will end pretty. Although it might be a case of f'(x)/g(x)

Integral over integral RG?

I just got k = 8 now

After intergration, it would be x - (k*x^3)/3 - (x^3)/3. Then you sub 1/root(k+1) and -1/root(k+1) into this and equate to 2/3.

so it will be

x ( 1 - ((x^2)/3)(k+1)) over which you sub +1/root(k+1) to -1/root(k+1).

When you sub this, you get 2/root(k+1) = 2/3. Hence k = 8.

Please check it guys.

@kiranr, very strange but according to Urban's calculations and my continuation we had 4/(3*root(k+1)) = 2/3 at that point.

@Spanky, test for k=3 or k=8 whether the calculations were right eco smile

You're our specialist in applied maths eco smile

by Babun Tue Sep 11, 2012 2:03 am

For all the interested parites, that's what German high schoolers need to know in maths in order to be able to study at an uni:
http://www.sendspace.com/file/pt4y8f
Maths- Gym for Brainiacs - Page 25 14047752796496505428

Maths- Gym for Brainiacs - Page 25 14047752796496505428

by RealGunner Tue Sep 11, 2012 2:08 am

urbaNRoots wrote:
Babun wrote:Are you a highschooler?

I study computer engineering, tried to solve this as I remembered the formula but got caught

In Germany ?

by Babun Tue Sep 11, 2012 2:59 am

k=3 was right kiranr:

Maths- Gym for Brainiacs - Page 25 Zmm9lmwi

Just tested :coffee:

Urban

by spanky Tue Sep 11, 2012 3:45 am

just got home Sad

by Babun Tue Sep 11, 2012 4:12 am

spanky489 wrote:just got home

Fun Question

Requirements: the ability to count till 9
Difficulty: unknown

Maths- Gym for Brainiacs - Page 25 M5m88scg

Nine 3s are ordered in a way that their horizontal, diagonal and vertical sum is 9. Order the nine 3s in a way that 10 series with the sum of 9 are created eco smile

The solution is graphical of course eco smile

by fatman123 Tue Sep 11, 2012 5:27 pm

i spent half an hour on this one and got nowhere Mad

by Babun Wed Sep 12, 2012 6:18 am

fatman123 wrote:i spent half an hour on this one and got nowhere

The solution is easy.

by RealGunner Wed Sep 12, 2012 6:21 am

do you make those lines into a 9 ?

by Babun Wed Sep 12, 2012 6:28 am

RealGunner wrote:do you make those lines into a 9 ?

Yeah, horizontal, vertical and diagonal lines with three 3s each which result in 9. YOu need 10 of those lines eco smile

by kiranr Wed Sep 12, 2012 9:45 am

3-------3
----3----
3---3---3
----3----
3------3

by Babun Wed Sep 12, 2012 7:18 pm

kiranr wrote:
3-------3
----3----
3---3---3
----3----
3------3

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