1+2-3+4-5......-99+100=
1-2+3-4+5-6+...+99-100=-50
1?
1-2=-1?3-4=- 1?5-6=-199-100=-11002?50?-1
1-2+3-4+5-6+...+99-100
=?1-2?+?3-4?+?5-6?+...+?99-100?
=-1 x 50
=- 50
2
1+3+5+7+...+992+4+6+...+100?
+?x ? /2?=?-?/+1
1+3+5+7+...+99?99-1?/2+1=50?2+4+6+.. .+100?100-2?/2+1=50
1-2+3-4+5-6+...+99-100
=?1 +3+5+7+...+99?-?2+4+6+...+100?
=?1+99?x50/2-(2+100)x50 /2
=2500-2550
=-50
?
Associated Press
d?
1,3,5,7,9?2n-1)? {instalar}? an=a1+(n-1)dn
+-1?/2?+?/ 2?