Question Number 9278 by j.masanja06@gmail.com last updated on 28/Nov/16
$$\mathrm{represent}\:\mathrm{in}\:\mathrm{sigma}\:\mathrm{notation}\: \\ $$$$−\mathrm{1}+\mathrm{4}−\mathrm{9}+\mathrm{16}.................. \\ $$
Commented by FilupSmith last updated on 28/Nov/16
$$=\underset{{n}=\mathrm{1}} {\overset{\infty} {\sum}}\left(−\mathrm{1}\right)^{{n}} {n}^{\mathrm{2}} \\ $$