# Why string theorist use the following result? [duplicate]

$1+2+3.......$so on $= -1/12.$ I have seen a few proofs of this result. And I hope most of you are familiar with them.

• Why string theorist use this ambiguous result in string theory, when assigning a value to a divergent sum is not acceptable to many mathematician?
• If this result is true; does it consolidate the belief that nature of ultimate reality cannot be perceivable by human mind.
• possible duplicate: Critical Dimension of Bosonic Strings and Regularization of $\sum_{n=1}^\infty n$ and linked questions there. Feb 21 '15 at 0:58
• See also Terry Tao's blog for a more or less rigorous mathematical treatment of this kind of regularisation. Feb 21 '15 at 0:59
• Read the "Divergent Series" chapter of Kline's History of Mathematics to see how infinite sums like these represent asymptotic approximations to well-defined functions :) Feb 21 '15 at 1:07