Arithmetic Series 2k: Sum of (-1)^n

[resresd]

2k
Σ (-1)n
N=1
i am meant to write it out in full and i know that the answer is 0 which i think i understand as it will be -1+1-1+1 etc, but i don't know what to do about the k, it doesn't say that it is a constant, is it safe to assume it is anyway? and what do i do if it is?
thanks
resresd

 

[Dick]

(-1)^n, right? Yes, k is a constant. 2k is the number of terms in -1+1-1+1... What's the sum? Hint: 2k is even.

 

[resresd]

yes sorry, i wrote it out in word and copy pasted it, the superscript obviously didn't show up. if 2k showa that the number of terms will be even then with the pattern of -1+1 the answere will be 0...how do i write it out though? is it just -1+1 with a recurring dot? can i do that?

 

[Dick]

The sum is 0, yes. Just write it using words, like '(-1+1)+(-1+1)+... k times =0+0+0+... k times=0'. Something like that.

 

[resresd]

Thanks