Rondam Ramblings: No, the sum of all the positive integers is not -1/12
" About a week ago, two British mathematicians named Tony Padilla and Ed Copeland, who produce a video blog called Numberphile, posted a video that purports to prove that the sum of all the positive integers is -1/12. It was making the usual geek rounds where I would have been content to let it circulate, but today the story was picked up by a naive and credulous reporter at Slate, where the story stands to do some real damage if not challenged."
....explanation and equation at referenced site....
"The flaw in both cases is the same: the algebraic rules that apply to regular numbers do not apply to infinity. Actually, it's more general than that: the algebraic rules that apply to regular numbers do not apply to non-converging infinite sums. All of the sums above are non-converging infinite sums, so regular algebraic rules to not apply. It is no different from using regular algebra when dividing by zero. It doesn't work.
Now, there are ways to define the sums of non-converging infinite series so that they do not lead to contradictions. The one that leads legitimately to the conclusion that 1 + 2 + 3 + 4 ... = -1/12 is called Ramanujan summation, which in turn is based on something called an analytic continuation. But the problem is that the Numberphile video makes no mention of this.
They present the result as if it is legitimately derivable using high school algebra, and it isn't. Telling people that it is does a grave disservice to the cause of numerical literacy."
Here is another informative explanation:
Does 1+2+3
Arithmetic - Wikipedia, the free encyclopedia
Arithmetic or arithmetics (from the Greek word ἀριθμός, arithmos "number") is the oldest[1] and most elementary branch of mathematics, used very popularly, for tasks ranging from simple day-to-day counting to advanced science and business calculations. It involves the study of quantity, especially as the result of operations that combine numbers. In common usage, it refers to the simpler properties when using the traditional operations of addition, subtraction, multiplication and division with smaller values of numbers.
I'm an old farmer with a degree in Mathematics
Loren