Originally posted by FabianFnas 1 + 1/2 + 1/4 + 1/8 + ... = 1
How about 1 + 1/2 + 1/4 + 1/8 + ... = 2 ?
Yes, in the thread we were actually discussing both the series 1/2 + 1/4 + 1/8 + ··· and 1 + 1/2 + 1/4 + ···, so it was a fairly natural mistake to make.
Originally posted by DeepThought Yes, in the thread we were actually discussing both the series 1/2 + 1/4 + 1/8 + ··· and 1 + 1/2 + 1/4 + ···, so it was a fairly natural mistake to make.
So now everyone agree that 1/2 + 1/4 + 1/8 + ... exactly = 1 finally...?
Originally posted by DeepThought Yes, in the thread we were actually discussing both the series 1/2 + 1/4 + 1/8 + ··· and 1 + 1/2 + 1/4 + ···, so it was a fairly natural mistake to make.
Originally posted by twhitehead Only on condition that the '=' does not mean quite the same as it does in normal equations. In this case the '=' is defined slightly differently.
It is seldom clear when you are being serious and when you are not.
Originally posted by Soothfast It is seldom clear when you are being serious and when you are not.
I am being serious. In this instance the final 'sum' of the sequence is defined as being the limit of the partial sums of the sequence. It is not the case that an infinite number of terms are actually added to give exactly 1.
Originally posted by twhitehead I am being serious. In this instance the final 'sum' of the sequence is defined as being the limit of the partial sums of the sequence. It is not the case that an infinite number of terms are actually added to give exactly 1.
If the sum (call it S) is not equal to 1.
Then what is (1 - S) ?
Originally posted by wolfgang59 If the sum (call it S) is not equal to 1.
Then what is (1 - S) ?
I do not believe the sum can be obtained. It is incoherent to talk of the sum of an infinite sequence without specifically redefining what we mean by 'sum'.
The problems associated with summing an infinite number of terms is especially noticeable when dealing with series that do not converge.