1、(1+1/2)×(1-1/2)×···×(1+1/1999)×(1-1/1999)=?
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/23 09:42:00
1、(1+1/2)×(1-1/2)×···×(1+1/1999)×(1-1/1999)=?
(1+1/1997+1/1998+1/1999)×(1/1997+1/1998+1/1999+1/2000)-(1+1/1997+1/1998+1/1999+1/2000)×(1/1997+1/1998+1/1999)=?
各位能做多少就做多少···········
第一题的答案是不是1000/1999············
(1/11+1/21+1/31+1/41)×(1/21+1/31+1/41+1/51)-(1/11+1/21+1/31+1/41+1/51)×(1/21+1/31+1/41)=?
(1+1/1997+1/1998+1/1999)×(1/1997+1/1998+1/1999+1/2000)-(1+1/1997+1/1998+1/1999+1/2000)×(1/1997+1/1998+1/1999)=?
各位能做多少就做多少···········
第一题的答案是不是1000/1999············
(1/11+1/21+1/31+1/41)×(1/21+1/31+1/41+1/51)-(1/11+1/21+1/31+1/41+1/51)×(1/21+1/31+1/41)=?
1.设1/1997+1/1998+1/1999=a
(a+1)×(a+1/2000)-(1+a+1/2000)×a
=a²+a+1/2000a+1/2000-a-a²-1/2000a
=1/2000
2.设1/21+1/31+1/41=a
(1/11+a)×(a+1/51)-(1/11+a+1/51)×a
=(1/11)×(1/51)
=1/561
(a+1)×(a+1/2000)-(1+a+1/2000)×a
=a²+a+1/2000a+1/2000-a-a²-1/2000a
=1/2000
2.设1/21+1/31+1/41=a
(1/11+a)×(a+1/51)-(1/11+a+1/51)×a
=(1/11)×(1/51)
=1/561
(1-1/2001)+(1-2/2001)+(1-3/2001)+······+(1-1999/2001)+(1-200
1+2/1+2/1的平方+2/1的立方······+2/1的1999次方,
1²+2²/1×2+2²+3²/2×3+······+2003²+20
计算:1*2分之1+2*3分之1+3*4分之1+···+1998*1999分之1+1999+2000分之1
计算:(-1)+(+2)+(-3)+(+4)+···+(-1999)+(+2000)=
计算【1-2的平方分之一】【1-3的平方分之一】·······【1-1999的平方分之一】【1-2000的平方分之一
1·2·3·4+1=5²; 2·3·4·5+1=11²; 3·4·5·6+1=19²;
简算:1999+199·9+19·99+1·999+2·111
求(2+5+8······+2000)-(1+4+7······+1999)的值.【简算】
简便计算:1·99×1999+1·99
一道数学题 简算 1/1× 2× 3+1/2×3×4+1/3×4×5+······+1/9×10×11=?
1.3×(1×2+2×3+3×4+···+99×100+100×101)=