3+4 = 4+3 this is the communitative property of addition.
4+3 = 4+(2+1) this is the definition of 3
4+(2+1) = 4+(1+2)
4+(1+2) = (4+1) +2 this is the associative property of addition
(4+1) +2 = 5+2 this is the definition of 5
5+2 = 5+(1+1) this is the definition of 2
5+(1+1) = (5+1) +1
(5+1) +1 = 6+1 this is the definition of 6
6+1 = 7 this is the definition of 7
(-7/2)*(-7/2) = 49/4
ok let's say you changed 35/4 to 49/4
you basically have (-1/2)*(-1/2) = (1/2)*(1/2) True.
but the next line is equivalent to -1/2 = 1/2 False.
Problem? sqrt(1/4) = 1/2 or -1/2
From this however we cannot say that 1/2 = -1/2
Yes you're right. It seems I can't multiply. You are also right in finding the flaw in the logic of my argument. Of course it's there. You don't actually think I can prove 3=4 without one do you? There is the more common 'proof' of 1=2 that uses dividing by zero.
Nice eyes spotting the mistake though. First time round it took me a while.
Originally posted by XanthosNZ Yes you're right. It seems I can't multiply. You are also right in finding the flaw in the logic of my argument. Of course it's there. You don't actually think I can prove 3=4 without one do you? There is the more common 'proof' of 1=2 that uses dividing by zero.
Nice eyes spotting the mistake though. First time round it took me a while.
Certainly, I didn't expect you to actually believe your proof. Good job thinking up the completing the square bit.