The Maths Topic

I’ve done 1 before and 3 is easy so im gonna let someone else solve them.

wolframalpha.com is a really good site, just search for an equation and it will solve it :smile: yes you are right

Here you can train equations aswell, its too easy for me but you might like it: mathsnet.net/algebra/equation.html

5x = 3 = 5x + 4
x + 3 = x + 4
x = x + 1
Therefore,
|x| = Infinity

no its invalid :razz: if you search for it on wolframalpha it says False.

Well, The Maths Topic exists, but anyway…

Hraesvelg: The final dollar goes to pay the bills of staying.
25 dollars is the sum they paid to stay at the room. 2 dollars they paid to the bellboy.

Therefore, a total of 27 dollars was being paid by them. 27/3 = 9. You shouldn’t have added two to the sum they paid - Since they have already paid it!

But that is the riddle, of course…

Problem 2:

[spoiler]The possibility for two repeated digits is, the 1° and the 2° (xxy), the 1° and the 3° (xyx), the 2° and the 3° (yxx);
First case: the 1° digit (the hundreds one) has 9 possibilities (from 1 to 9), the 3° one is free and can be 10 numbers (0-9), so it’s 910=90 numbers
Same with the second case: 90 numbers.
For the third case, first digit can be 9 numbers, the other two can be 10, so it’s still the same: 9
10= another 90 possibilities.
But wait! We counted the single-digit numbers three times! (111, 222, etc.) so we must subtract 9*2=18 to the sum, making 90+90+90-18=252 numbers.
The remaining ones are therefore (999-100+1) - 252 = 900 - 252 = 648.[/spoiler]

Problem 3:[spoiler]After spending on clothes, she has half the money left; after games, it’s 1/2 - (1/2 * 1/3) = 1/3; after toys, it’s 1/3 - (1/3 * 1/4) = 1/4 money left.
So it’s x/4=7777, so x = 21108, where x is yearly allowance. To get a single month, we do x/12= 7777/3 = 2592,33.[/spoiler]

Not having math problems but I found a few interesting mathematical stuff :tongue:

You can for example turn around 1212=144 to 441=2121

Same thing goes for 1313=169|961=3131 or 1111=121|121=1111 :razz:

The answer to everything^2 is 1764 :tongue: and 1337^2 is 1787569 :grin:

Im trying to find more funny patterns :happy:

Something notable is that

[13.37 * pi] = 42

where [x] denotes the largest possible integer that is < x. Actually, even without the [], it is accurate to two decimals. :tongue:

the gravitational pull of a planet compared to earth is 3:8 or 3/8 a new moon starts to orbit the other planet making the gravitational pull 5x stronger what is the new ratio? it took me a while to figure that out myself :tongue:

Math/Physics Problem… Solve it for cookies.

(Let’s just say that 1g = 9.8 m/s^2 instead. That is equal to 9.8 newtons of force per square kilogram. :wink: :grin: )

You drop a 1000kg object from 1km high. If it were to fall at a steady rate of 9.8 meters per second, how much force will it undergo when it hits the ground?

lets find the determinant of [A]!! :smile:
1 3 4
[A]= 2 6 2
5 0 1

Expand row 3!!

    3  4                            1   3

5 – 6 2 + 1 – 2 6

=5[3(2)-6(4)] + 1[1(6)-2(3)]
=5[6-24] + 1[6-6]
=5[-18] + 0
= -90!!!

yayy!!

It depends on how long the collision lasts. Longer lasting collisions will result in a smaller average force. The impulse, however, can be calculated:

kinetic energy = 0.5 * mass * velocity^2
potential energy = mass * gravitational acceleration * height
kinetic energy = potential energy
0.5 * mass * velocity^2 = mass * gravitational acceleration * height
velocity = sqrt(2 * gravitational acceleration * height)

impulse = difference in momentum
difference in momentum = final momentum - initial momentum = mass * (0 - initial) = mass * sqrt(2 * gravitational acceleration * height) = 1000 * sqrt(2 * 9.8 * 1000) = 140,000 Ns

God, I’m still in Geometry and High school O_o, so I dunno what’s going on here ^_^.

Best I know?

3x-2 is parallel to 3x-12 on a grid. :happy:
-1/3x + 17 is perpendicular to 3/1x + 1,000 on a grid. (I think anyways, still a freshmen in high school :razz:)

<.< >.>

I don’t know much either.
Except the Infinity - Infinity isn’t indeterminate. It’s 0. :smile:

how long is the piece of string -------------------------------------------

A: since you dont know the exact length its the amount it takes for the right side to get to the left side(vice versa)multiplied by two, right?

342 Pixels? :grin:

haha lol no its just an example :tongue:

Explain.

Hmmm…

Well, Infinity, subtracted by itself, should be zero.

Because even though it is unlimited, no further numbers exist.
So even though Infinity + 5 = Infinity, Infinity = Infinity, never something greater, because nothing greater exists. So just treat Infinity like a number.
So Infinity - Infinity = 0. :grin:
If it is true, Infinity - Infinity - Infinity = -Infinity, because 0 - Infinity = -Infinity.

There is no number such as infinity. And even it there were, it would not hold under arithmetic axioms.

I’ll have to repeat: There is no “infinity” number.

Something subtracted by itself is always 1.
edit: oops my fault, meant divided.

In my opinion Infinity+5=Infinity+5 just like x+5=x+5, even tho nothing is bigger then infinity…