Mathematical "Proofs"

[brunokiller]

^ can't take the root of a negative number because there is no number which, multiplied by itself, gives a negative.

 

 

 

He never took the square root though.

 

 

 

In conventional mathematics without complex numbers, you can't even write down -1^0.5

 

 

 

Doesn't it just work out to be -1 though?

 

 

 

-1^0,5 =/= -1

 

 

 

It's i.

[Kiriyama]

Yeah okay, I'll take your word for it.

 

 

 

Honestly, things get complicated as soon as someone introduces the concept of infinity.

[brunokiller]

http://en.wikipedia.org/wiki/Limit_(mathematics)

 

 

 

Closest you will ever get to infinity in normal math class :P

[ydrasil]

(1^(1/2)/-1^(1/2)) = (-1^(1/2)/1^(1/2))

 

 

 

1/i =- i/1

 

 

 

1/i = -i

 

 

 

As 1^0.5 x -1^0.5 = i,both sides times i.

 

 

 

1 = 1.

 

I was about to show the exact same thing but without the complex numbers. Your way works just the same though : :

 

[Rebdragon]

-

[20Rice04]

^ can't take the root of a negative number because there is no number which, multiplied by itself, gives a negative.

 

incorrect, use of the integer I or J in physics allows the root of a negative number.

 

 

 

the actual mistake is the belief that the root of an entire fraction is the same as the root of the nominator and denominator, this is infact FALSE fo all all numbers belonging to the set of real numbers.

[mmmcannibalism]

^ can't take the root of a negative number because there is no number which, multiplied by itself, gives a negative.

 

incorrect, use of the integer I or J in physics allows the root of a negative number.

 

 

 

the actual mistake is the belief that the root of an entire fraction is the same as the root of the nominator and denominator, this is infact FALSE fo all all numbers belonging to the set of real numbers.

 

 

 

to be technical, no number can be written that is the square root of a negative number, we use things such as i to allow work that involves such "complex" numbers.

[wild_goat_14]

(1^(1/2)/-1^(1/2)) = (-1^(1/2)/1^(1/2))

 

 

 

1/i =- i/1

 

 

 

1/i = -i

 

 

 

As 1^0.5 x -1^0.5 = i,both sides times i.

 

 

 

1 = 1.

 

I was about to show the exact same thing but without the complex numbers. Your way works just the same though : :

 

 

 

 

Or the fast way...

 

 

 

-1=-1

 

-1(-1)=-1(-1)

 

1=1

 

I know you are just disproving someone else's equation, I just really had the urge to post that.

[20Rice04]

^ can't take the root of a negative number because there is no number which, multiplied by itself, gives a negative.

 

incorrect, use of the integer I or J in physics allows the root of a negative number.

 

 

 

the actual mistake is the belief that the root of an entire fraction is the same as the root of the nominator and denominator, this is infact FALSE fo all all numbers belonging to the set of real numbers.

 

 

 

to be technical, no number can be written that is the square root of a negative number, we use things such as i to allow work that involves such "complex" numbers.

 

 

 

you can write it it's just not technically correct as i itself can neither be positive or negative, how silly we humans are :wall: :P

[warri0r45]

I don't have a mind for maths, unfortunately. Whenever I think of a mathematical problem I do best to keep it simple and, if possible, think of each unit as a physical object.

 

 

 

For example, I rationalise dividing by zero to be nonsensical because you can't divide a number of objects into zero groups. They'll always be in groups, even if it's just groups of one.

 

 

 

Then you might have a mind for physics,

 

where every number has set significance and you are not left in a void of variables and symbols with no meaning.

 

 

 

Perhaps. I think that I have a mind for molecular biology more than anything else. It's all easily understandable on a physical level. It's too late to seriously consider any other field of science anyway.

[deathdrow]

god I love these math threads.

[Boris5000]

infinity x 0 x 2 = 1

 

 

 

infinity x 0 = 0

 

 

 

0 x 2 = 0 (not 1)

 

 

 

Whats next. Are you goign to discard the fabric of life by proving;

 

1+1 does not = 2?

 

 

 

Or that the trig functions are incorrect?

 

 

 

Or you can magically apply pytharogas's theoreom to a equilateral triangles... (Yes it is possible, I realise that...)

 

 

 

EDIT: Yeah, I just read the first post ;-; I failed epically.

 

 

 

But yeah, people have been applying wrong algebraic equations, etc... (silly people)

[l0l0lpur34]

If you can find the error here I'll be bloody impressed :P

 

 

 

-1 = -1

 

 

 

(1/-1) = (-1/1)

 

 

 

(1^(1/2)/-1^(1/2)) = (-1^(1/2)/1^(1/2))

 

 

 

multpily by 1^(1/2).-1^(1/2) and you get

 

 

 

1= -1

 

 

 

Q.E.D PLAWKS?

 

(1^(1/2)/-1^(1/2)) = (-1^(1/2)/1^(1/2))

 

 

 

1/i =- i/1

 

 

 

1/i = -i

 

 

 

As 1^0.5 x -1^0.5 = i,both sides times i.

 

 

 

1 = 1.

 

I was about to show the exact same thing but without the complex numbers. Your way works just the same though : :

 

 

the rule sqrt(a) * sqrt(B) = sqrt(ab) only applies for real numbers, and sqrt(-1) isn't a real number.

[Cacmypants]

Lol, may I ask... why?

 

 

 

WHY!? :wall: