So no one knows how to answer this?
Suppose r and s are positive integers with no common factor and
1 - 1/2 + 1/3 - 1/4 + ... + 1/1339 - 1/1340 = r/s
Find a prime factor of r.
Have no idea how to solve this so please help.
Please explain it step by step clearly. Thanks.
Oh no, many of us know what needs to be done.
But why do you think we should do your work for you?
Here it is.
Now what can you do with that?