Random picture thread

ok, heres something especially for Merko and John:

2x2.gif
 
BodomiC said:
Actually, those calculations are incorrect on the passage from line 5 to line 6.

Line 5:
(4 - 9/2)^2 = 0.25
(5 - 9/2)^2 = 0.25

Line 6:
5 - 9/2 = 0.5
4 - 9/2 = -0.5

It is not true that

x = y <=> x^2 = y^2

What is true is that
x = y => x^2 = y^2
but x^2 = y^2 does not mean that x = y

I'll post a simple example of this.

Take 2^2 = (-2)^2 for instance.
2^2 = 4
(-2)^2 = 4

BUT

2 != -2


Ok, now that I've made a nerd out of myself I'll just go hide in the corner. :p
 
DarkMare said:
Actually, those calculations are incorrect on the passage from line 5 to line 6.

Line 5:
It is not true that

x = y <=> x^2 = y^2

What is true is that
x = y => x^2 = y^2
but x^2 = y^2 does not mean that x = y
yeah, but see that x^2=(-x)^2 so y^2 can be both (-y)^2 or just y^2... so that means that this line can be true :lol:
 
BodomiC said:
yeah, but see that x^2=(-x)^2 so y^2 can be both (-y)^2 or just y^2... so that means that this line can be true :lol:
x^2 = y^2
only means that
|x| = |y|

In other words
x = y OR x = -y

on the image above they only considered the option x = y, which was completely incorrect (they ended up with 0.5 = -0.5).