1
$\begingroup$

A weird infinity problem. I saw this on youtube but could not understand it:
Let us add 1 + 2 + 4 + 8 + 16 + ... up to infinity
x=(1+2+4+8+...)
= 1(1+2+4+8+...) = (2-1)(1+2+4+8+...) = (2+4+8+16+...)-(1+2+4+8+...) = -1
x=-1


Now that is weird since we are adding up to infinity towards the positive side yet we end up with a negative number. Somebody please explain me why.

$\endgroup$

Browse other questions tagged or ask your own question.