MathMania

spyrothepalmontcityracer · Mar 15, 2015 3:43 PM

So, how about a math game, calculators be prepared.

i'll start with multiplication

7 X 5

NeoReaper · Mar 15, 2015 5:51 PM

35.
π =?

Last edited by NeoReaper (Mar 15, 2015 5:52 PM)

spyrothepalmontcityracer · Mar 15, 2015 6:02 PM

3.14159265

convert 50.00USD into British Pounds.

Gekoncze · Mar 15, 2015 6:59 PM

33.9

Let x € R, y = x^2 + 3x + 5
y' = ?

spyrothepalmontcityracer · Mar 29, 2015 12:20 AM

Wow Gekoncze, that one's hard!

Gekoncze · Mar 29, 2015 11:04 AM

Nobody wants to solve it sad

Scaler · Mar 29, 2015 12:44 PM

€R, as in the hospital.

I'm not that far in math yet, buddy.

Paranoia · Mar 29, 2015 5:18 PM

It's been a while since I've had a Calculus class, but I think this is right:

y'=2x+3

Seems like a simple derivative? Now if you had one with the chain or power rule I probably wouldn't remember how to solve it. Not sure what Let x € R means though so I could be completely wrong.

A large box rests on an icy surface. Someone pulls on the box with a Force = 10 N at a angle 37 degrees above the horizontal. If there is no friction between the box and ice, what is the change in the box's kinetic energy after moving 5 meters? (I found my old physics notebook in my room tongue )

Sheep · Mar 29, 2015 7:09 PM

Let x € R probably just means that x can be any, Real number.

I haven't had any physics classes yet, so I don't know what any of those terms really mean neutral
But with Wikipedia to help me...

The standard unit of kinetic energy is the Joule.

J = N*m

1 N = 1 kg⋅m/s2

Well, that wasn't a lot of help xD Both time and mass is not mentioned in your problem. And when is the change in kinetic energy compared to? When the box was resting, or the moment of the initial pull? And is the pulling force only applied a single instant, or continuously?

The lack of friction tells me the box shouldn't lose any of the speed it has gained.
I'm guessing that the box isn't lifted off the surface, and that the 37 degrees means the force should become 10 N * cos(37) =~ 7.99 N.

If the pull is continuous, and the comparison applies to the initially resting box...
Change in box's kinetic energy = 7.99 N * 5m = 7.99*5 J = 39.95 J ???
Am I anywhere near? xD

Given a 12x19 cm rectangle, what is the combined length of all sides plus diagonals?

Last edited by Sheep (Mar 29, 2015 7:14 PM)

Gekoncze · Mar 29, 2015 7:12 PM

*got ninjad*

Last edited by Gekoncze (Mar 29, 2015 7:14 PM)

Paranoia · Mar 29, 2015 8:00 PM

Yeah, you got it Sheep--nice! The way we solved it was that "change in kinetic energy" is equal to Work. And Work=Force*Distance, taking into account the trigonometry. Now if there was more of a directional aspect (forward, backward) to the problem and the units weren't standard SI...then it would have been much more difficult. I did not enjoy Physics...lol. Or I should say, I didn't like my teacher; the subject material was interesting.

Given a 12x19 cm rectangle, what is the combined length of all sides plus diagonals

See if my quick Pythagorean theorem was right: 106.9 cm

Sheep · Mar 30, 2015 10:56 AM

106.9 cm seems right to me smile

Now lets do one with imaginary numbers!

'i' is an imaginary unit defined by it's property i^2 = -1.

imaginary number = real number * i.
Example: 2i

complex number = real number + imaginary number.
Example: 5 + 2i

So for example, we have the imaginary number 4i.
It is multiplied with a real number like this:
3 * 4i = 12i
And with an imaginary number, like this:
2i * 4i
= 2*4*(i*i)
= 8*(i^2)
= 8*(-1)
= -8

Now, multiply the complex number (1 + 2i) with the imaginary number 3i.

(1 + 2i) * (3i) = ?

Last edited by Sheep (Mar 30, 2015 10:58 AM)

#1 Mar 15, 2015 3:43 PM

MathMania

#2 Mar 15, 2015 5:51 PM

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#3 Mar 15, 2015 6:02 PM

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#5 Mar 29, 2015 12:20 AM

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#6 Mar 29, 2015 11:04 AM

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#7 Mar 29, 2015 12:44 PM

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#9 Mar 29, 2015 7:09 PM

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