1+2+.............999+1000=
2006-10-29 12:35 am
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+...............................................981+982+983+984+985+986+987+988+989+990+991+992+993+994+995+996+997+998+999+1000=
回答 (18)
2006-10-29 12:39 am
✔ 最佳答案
1+1000 = 10012+999 = 1001
3+998 = 1001
:
:
:
499+502 = 1001
500+501 = 1001
= 1001 x 500
= 500500
2006-10-29 7:32 am
= (1 + n)n/2
= (1 + 1000)1000/2
= 500500
= (1 + 1000)1000/2
= 500500
2006-10-29 2:44 am
這條數可用下列方程式去計算：
(首項+尾項)*項目總數/2
因此，答案是(1+1000)*1000/2 = 500500
(首項+尾項)*項目總數/2
因此，答案是(1+1000)*1000/2 = 500500
2006-10-29 1:55 am
1+2+3+..............................+998+999+1000
=(1+1000)*1000/2
=1001*500
=500500
=(1+1000)*1000/2
=1001*500
=500500
2006-10-29 12:50 am
Sum of arithmetic series:
Sn=n/2 ( a + L )
a=first term
n=nth term
L=last/ nth term
a=1
n=1000
L=1000
Sn=1000/2(1+1000)
=500500
or
Sn=n/2(2a+(n-1)d)
a=first term
n=nth term
d=common difference
a=1
n=1000
d=1
Sn=1000/2 ( 2x1+ (1000-1)1)
=500500
Sn=n/2 ( a + L )
a=first term
n=nth term
L=last/ nth term
a=1
n=1000
L=1000
Sn=1000/2(1+1000)
=500500
or
Sn=n/2(2a+(n-1)d)
a=first term
n=nth term
d=common difference
a=1
n=1000
d=1
Sn=1000/2 ( 2x1+ (1000-1)1)
=500500
2006-10-29 12:43 am
2006-10-29 12:39 am
連續數有一個公式去計算，就是
(第一個數+最後一個數)X(數量)再除2
以你上述一題為例就是
(1+1000)X1000除2
=1001X1000除2
=500500
(第一個數+最後一個數)X(數量)再除2
以你上述一題為例就是
(1+1000)X1000除2
=1001X1000除2
=500500
2006-10-29 12:39 am
〔（ 首項+尾項 )÷2 〕X 尾項
=〔（ 1+1000 ) ÷ 2 〕X 1000
= ( 1001 ÷ 2 ) X 1000
= 500.5 X 1000
= 500500
=〔（ 1+1000 ) ÷ 2 〕X 1000
= ( 1001 ÷ 2 ) X 1000
= 500.5 X 1000
= 500500
參考: My mind
2006-10-29 12:38 am
500500
2006-10-29 12:37 am
500*1001=500500
收錄日期: 2021-04-12 18:06:23
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20061028000051KK03066