Răspuns :
= -(2+4+6+...+2000)
= -[2(1+2+3+...+1000)]
= -(2*1000*1001:2)
= -(1000*1001)
= -1001000
= -[2(1+2+3+...+1000)]
= -(2*1000*1001:2)
= -(1000*1001)
= -1001000
-2-4-6-8-10-...-2000=
=-2(1+2+3+4+5+...+1000)=
=-2· 1000(1000+1)/2=
=-2·1000·1001/2=
=-1·1001000=-1001000
=-2(1+2+3+4+5+...+1000)=
=-2· 1000(1000+1)/2=
=-2·1000·1001/2=
=-1·1001000=-1001000