(1-1/2^2)(1-1/3^2)……(1-1/2004^2)=?
来源:百度知道 编辑:UC知道 时间:2024/04/28 23:14:47
(1-1/2^2)(1-1/3^2)……(1-1/2004^2)=
1-1/n^2=(n^2-1)/n^2=(n-1)(n+1)/n^2
(1-1/2^2)(1-1/3^2)……(1-1/2004^2)
=1*3/2^2*2*4/3^2*3*5/4^2*...*2003*2005/2004^2
=(1*2005)/(2*2004)
=2005/4008.
0
1-1=0
0/任何数=0
0乘任何数=0
所以最后还是0
2005/4008
不懂上HI百度
=(1+1/2)(1-1/2)(1+1/3)(1-1/3)...(1+1/2004)(1-1/2004)
=(1+1/2)(1+1/3)...(1+1/2004)((1-1/2)(1-1/3)...(1-1/2004)
=3/2*4/3*5/4*...*2005/2004*1/2*2/3*3/4*...*2003/2004
=2005/2 *1/2004
=2005/4008
原式=(1-1/2)(1+1/2)(1-1/3)(1+1/3)........(1-1/2004)(1+1/2004)
=(1-1/2)(1-1/3)......(1-1/2004)(1+1/2)(1+1/3).....(1+1/2004)
=(1/2)(2/3)(3/4)...(2003/2004)(3/2)(4/3)...(2004/2003)(2005/2004)
=(1/2)(2005/2004)
=2005/4008
1+1/(1+2)+1/(1+2+3)+...+1/(1+2+3+...+100)
1+1/(1+2)+1/(1+2+3)+-------+1/(1+2+3+----+100)
1+1/1+2+1/1+2+3+...+1/1+2+3...+2000
1+1/1+2+1/1+2+3.........+1/1+2+3.....100
1*(1/1+2)*(1/1+2+3)*~~~*(1/1+2+~~~2005)=?
(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)
(1-1/2^2)*(1-1/3^2)*(1-1/4^2).......(1-1/100^2)
1/2-1/2=?
3/2=2+1/1*2=1/1+1/2
(1/2005-1)(1/2004-1)........(1/3-1)(1/2-1)