Maths quiz

[Dell19]

To make up for the spam threads being closed, its our duty to create some new quizzes and other interesting none spam word games...

So heres the maths quiz. The main problem will be doing squared numbers currently we could do powers like this X^4. This would be X to the power of 4...

First easy question is to integrate 2x

 

[Michiel de Ruyter]

x^2 + c ( constant )

 

[ainwood]

a.) What's the next number in the series:
1,3,6,10,15?

b.) What are these numbers called (in relation to this series?)

 

[IceBlaZe]

Originally posted by ainwood
a.) What's the next number in the series:
1,3,6,10,15?

>>> 21

b.) What are these numbers called (in relation to this series?)

>>> withdrawal seris?

The formula of the series is possibly:
a(n)=a(n-1)+n

it is a withdrawal seris

 

[Wolfe Tone]

I was always taught that they are triangular numbers (I hope I am remembering this right)

 

[Lucky]

Isn´t the usual quiz rule applicable here, too?

The first to answer a question correct, get´s to ask the next one!

Otherwise this will turn into blatant spamming and will be closed!

So it is Michiel de Ruyter turn!

 

[MCdread]

Originally posted by Dell19


First easy question is to integrate 2x

If you don't give the limits of integration, then you probably meant the primitivation of 2x.

 

[damunzy]

I also though that this board was English only?!?
I can see with these questions this is the last time I need come in here as I am on the 2+2 level.

 

[Knight-Dragon]

Originally posted by Dell19
To make up for the spam threads being closed, its our duty to create some new quizzes and other interesting none spam word games...

Yeah, and who do we have to thank for that. J/k.

Hey, no fair. I have left behind my math days eons ago. Only you student types can play at this.

 

[allhailIndia]

Slightly harder

THe perimeter of a right angled triangle is 8cm. If one of the sides of the Triangle be 3cm, what should the other two sides be for max area.


Give some reasoning or proof

 

[ainwood]

Originally posted by Lucky
Isn´t the usual quiz rule applicable here, too?

The first to answer a question correct, get´s to ask the next one!

Otherwise this will turn into blatant spamming and will be closed!

So it is Michiel de Ruyter turn!

Lucky - Don't know if it would be considered "spam", however I take your point (and I also asked out-of-turn on the geography one).

Regardless:

I apologise for not following the implied rules..

Originally posted by Wolf Tone I was always taught that they are triangular numbers (I hope I am remembering this right)

That is what I was after. If its really a withdrawl series, then IceBlaze has to leave us and go play with the "real" mathematicians!

 

[Lovro]

Originally posted by allhailIndia
THe perimeter of a right angled triangle is 8cm. If one of the sides of the Triangle be 3cm, what should the other two sides be for max area.

IIRC, it is solved via square equations (I don't know if that's what they're called in English... help? ).

However, there is no way I'm remembering it now

 

[ainwood]

2.4 cm² is the maximum area, when one of the other sides is 1.6cm long, and the other (the hypotenuse) is 3.4cm long.

If one side is 3cm long, then this cannot be the hypotenuse.

Eg. Let the other sides be A & B.

If the Hypotenuse is 3 cm long, then:
3² = A² + B² and A + B = 5
Hence, 9 = A² + (5-A)²; This has no real roots. Hence, the hypotenuse cannot be 3cm long.


So: Let the Hypotenuse be B cm long.
3² + A² = B² and B = 5 - A.

So: 9 + A² = (5 - A)²
=> 9 + A² = 25 -10A + A²
hence: A = (25-9)/10
= 1.6

So: Area = 1/2 x 3 * 1.6
= 2.4cm².


A = 1.6 cm
B = 3.4 cm

 

[ainwood]

Well Allhail? Is this right?

 

[allhailIndia]

Unfortunately you are wrong ainwood. Give it another try and see where you made that mistake.

HINT:Try a bit of differentiation

 

[Dell19]

Just ask the next question to keep the game running. If its wrong then the question can be reposted and the person who gets it right can ask the question after yours.

 

[IceBlaZe]

EDITED: Bad answer

 

[IceBlaZe]

Sorry for the messy traingular drawing... looks better no notepad

 

[Lucky]

Actually I think ainwood is correct!

Why don´t you explain your differentiation method!

 

[Hitro]

What was wrong about ainwood's answer?

3 can't be the Hypotenuse, that's for sure.
Therefore the area has to be (3/2)*a. (because (a*b)/2 and b=3).
Now a=1.6 is the correct answer.
The only way to let the area grow would be to let a grow, as b is constant. But if a grows you would have to shrink c (the Hypotenuse) because a+c=5. Then it would no longer be a retangular triangle.

Please tell me where ainwood and me (EDIT: and Lucky) are wrong please.