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Message Board > Malarkey > Mathematical frustrations <3

April 26, 2013, 12:37
Zomg
None
641 posts
I would like to share with you all my mathematical frustrations. I spent 1 hour and thirty minutes racking my brain on equations, while making stupid mistakes such as distributing division with right hand left side terms (which is not allowed in math!)

Behold:









Freaking math. Damn man. =P
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April 29, 2013, 09:54
Dennis
どこかにいる
2050 posts

Find x,y:

sqrt(7y + 10x) = x + y

find x,y,z,a,b,c:

sqrt(8y+12-27/z + (3c^3) + b) = ((12x-3z+a-(b^2))*(-3)-1)*-1

[Edited on April 29, 2013 by Dennis]
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Kwakkel
#
April 29, 2013, 11:13
Dennis
どこかにいる
2050 posts

The first one is x=6 and y=3, but you can also use x=0 and y=0


These are bad examples.


Never mind.

[Edited on April 29, 2013 by Dennis]
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Kwakkel
#
April 29, 2013, 14:43
Zomg
None
641 posts
=P. Yes, I do not know how to do two-term (discriminant), four-term (quadratic) or further (unchain in factorials) equations. I am still at equations with one unknown, which suffices for Kots Accounting. =D

We still have to work with stuff like vierkantsvergelijking, if you are familiar with this. It's a little number in front of a sqrt() sign. Like: sqrt()
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April 30, 2013, 09:41
Dennis
どこかにいる
2050 posts

I think you mean square root (vierkantswortel) cube root (derdemachtswortel) and n root (dunno the dutch term)

a square root, is finding the factor that multiplies itself

vierkantsvergelijking is an quadratic equation like a + bx + c = 0


SQRT tutorial

sqrt sqrt sqrt!

Just kidding.

Real SQRT tutorial

sqrt(25) = 5, because 5 = 25. Finding a square root is done by guessing, learning by heart, or using a calculator. There IS a method to do it with pencil and paper but those still require some guessing, so it's best to use a calculator.


This is the order:

ALWAYS: Between brackets from deepest level and up FIRST! Locate the brackets and solve them first.

1. powers and roots: roots: do what's under the upper line of √ first!
2. multiply and division: left to right
3. adding and substraction: left to right

example:

__________
√8-1+2*5 + 4 -(8+3*(7+3))


Locate deepest brackets and solve what's between them so you can remove the brackets:

__________
√8-1+2*5 + 4 -(8+3*(7+3))

It's solved so we can go a level higher:

__________
√8-1+2*5 + 4 -(8+3*10)

Follow the order above.

1: powers and roots -> none

2: multiplying and division:

__________
√8-1+2*5 + 4 -(8+3*10)

__________
√8-1+2*5 + 4 -(8+30)

3: adding and substraction:

__________
√8-1+2*5 + 4 -(38)

Remove the brackets if there are no more operations:

__________
√8-1+2*5 + 4 -38

There are no more brackets, but what's under the root's upper line is considered "between brackets":

___________
8-1+2*5 + 4 -38

1: powers and roots:

___________
8-1+4*5 + 4 -38

2: multiplying and division:

__________
8-1+20 + 4 -38


3: adding and substraction (from LEFT to RIGHT)

_________
8-1+20 + 4 -38

_______
√7+20 + 4 -38

____
√27 + 4 -38

No more operations below the root's upper line! No more brackets to be found nowhere!

1: powers and roots:

____
√27 + 4 -38


Guess:
____
√27 = x

do this operation on both sides: ^3

27 = x <=>
27 = x*x*x <=>
27 = 3*3*3 // so the result is 3.

Use a calculator to omit that shit and see "3" on your screen.

2: Multiplying and division: none

3: adding and substraction: (from LEFT to RIGHT)

3 + 4 - 38

7 - 38

eventual result: -31




by the way: note that a SQUARE root can have 2 results: x and -x.

5*5 = 25
-5*-5 = 25

sqrt(-25) or sqrt(-16) results to the imaginary number i, because there is no real number that can result to a negative result squared. See the result as a variable. So mind that (-x)*(-x) is always positive, (You can clearly see why if you draw it on a graph) except i*i. That's why sqrt(25) can be either 5 or (-5).

The result of x is always positive, but the special imaginary number i results to -x when squared. We actually agree to it that there EXISTS a special number that we cannot represent visually that CAN result into a negative number squared. This may look weird at first, but it is not weirder than Romans who found it weird to represent 0 as a number. They were like: "why use a number for something that doesn't EXIST? Why use "nothing" in a calculation? You cannot sell 0 breads, it's pointless!"


Well this is the same case with i.

Also: follow reason is why 0 doesn't exist in roman numerals! ;)





Bien toi
Kind regards
Vriendelijke groeten
あなたに感謝し、敬具
____________
Kwakkel
#
April 30, 2013, 11:43
Zomg
None
641 posts
Thank you ^1000000000, Dennis. You are a nice and patient person. =)

I always wondered in French what 'BoT' meant, by I quickly figured out it was indeed 'Bien toi'. =P
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Message Board > Malarkey > Mathematical frustrations <3

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