Hi, all!
Recently I calculated some summations, such as:
. . . . .\(\displaystyle \displaystyle \sum_{k=1}^n\, k\, =\, \dfrac{n\,(n\, +\, 1)}{2}\)
The idea of the summation of cos(k) just popped up in my head:
. . . . .\(\displaystyle \displaystyle \sum_{k=1}^n\, \cos(k)\, =\, ?\)
I have googled a lot, but none of the results seems to be about this kind of question.
Recently I calculated some summations, such as:
. . . . .\(\displaystyle \displaystyle \sum_{k=1}^n\, k\, =\, \dfrac{n\,(n\, +\, 1)}{2}\)
The idea of the summation of cos(k) just popped up in my head:
. . . . .\(\displaystyle \displaystyle \sum_{k=1}^n\, \cos(k)\, =\, ?\)
I have googled a lot, but none of the results seems to be about this kind of question.
Attachments
Last edited by a moderator: