(1/8+1/9+1/10+1/11)X(1/9+1/10+1/11+1/12)-(1/8+1/9+1/10+1/11+1/12)X(1/9+1/10+1/11)

来源：百度知道编辑：UC知道时间：2024/05/28 00:52:53

要答得准确和详细步骤

令a=1/9+1/10+1/11

(1/8+1/9+1/10+1/11)X(1/9+1/10+1/11+1/12)-(1/8+1/9+1/10+1/11+1/12)X(1/9+1/10+1/11)
=(1/8+a)*(a+1/12)-(1/8+a+1/12)*a
=(1/8+a)*(a+1/12)-(1/8+a)a-1/12*a
=(1/8+a)*a+1/12*(1/8+a)-(1/8+a)a-1/12*a
=1/12*(1/8+a)-1/12*a
=1/12*1/8+1/12*a-1/12*a
=1/96

1/96 把1/8+1/9+1/10+1/11+1/12看做已知结果t.那么（t-1/12）*（t-1/8）-t*（t-1/8-1/12）展开就刚好消去t得出结果 =1/96

(1/8+1/9+1/10+1/11)X(1/9+1/10+1/11+1/12)-(1/8+1/9+1/10+1/11+1/12)X(1/9+1/10+1/11)
=1/96

1/8=1/( )+1/( )1 1/10=1/( )+1/( ）1/12=1/( )+1/( )+1/( ) 1-1/4 -1/8-1/16-1/32-1/64 1/8决赛? 1/8=1/（）+1/（） 1/2+1/4+1/8+1/16......+1/256=? 1/6+1/8+1/10+1/12+..........+1/202=? 1/2+1/4+1/6+1/8+.......+1/n=? 一:1／8＝1/( )+1/( )二:1/10=1/( )+1/( )三:1/12=1/( )+1/( )+1/( ) 1/(2+5)+1/(5+8)+1/(8+11)+1/(11+14)+...+1/(47+50) 1/3*5+1/5*8+1/8*11+......+1/98*101