In: Advanced Math
Prove that if ∑an converges absolutely, then both ∑Pn and ∑Nn converge
If converges absolutely then series converges.
are positive terms of series
and are negative terms of series .
Since series and both converges.
Therefore, their sum also converges
=> also converges
=> converges
Similarly, as and converges.
Therefore, also converges
=> also converges.
=> converges.
Hnece, and converges if converges absolutely.