165又40/1除以41/1 等以多少,用简便运算,2/1+6/1+12/1+20/1+30/1=?(1+2/1)*(1-2/1)*(1+3/1)*...*(1+9/1)*(1-9/1)=?2001/1+2001/2+2001/3+02001/4+...+2001/2001=?(10-10*55/40+(9-9*55/4)+...+(1-1*55/4)=?急.急.
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![165又40/1除以41/1 等以多少,用简便运算,2/1+6/1+12/1+20/1+30/1=?(1+2/1)*(1-2/1)*(1+3/1)*...*(1+9/1)*(1-9/1)=?2001/1+2001/2+2001/3+02001/4+...+2001/2001=?(10-10*55/40+(9-9*55/4)+...+(1-1*55/4)=?急.急.](/uploads/image/z/68228-44-8.jpg?t=165%E5%8F%8840%2F1%E9%99%A4%E4%BB%A541%2F1+%E7%AD%89%E4%BB%A5%E5%A4%9A%E5%B0%91%2C%E7%94%A8%E7%AE%80%E4%BE%BF%E8%BF%90%E7%AE%97%2C2%2F1%2B6%2F1%2B12%2F1%2B20%2F1%2B30%2F1%3D%3F%EF%BC%881%2B2%2F1%EF%BC%89%2A%EF%BC%881-2%2F1%EF%BC%89%2A%EF%BC%881%2B3%2F1%EF%BC%89%2A...%2A%EF%BC%881%2B9%2F1%EF%BC%89%2A%EF%BC%881-9%2F1%EF%BC%89%3D%3F2001%2F1%2B2001%2F2%2B2001%2F3%2B02001%2F4%2B...%2B2001%2F2001%3D%3F%EF%BC%8810-10%2A55%2F40%2B%EF%BC%889-9%2A55%2F4%EF%BC%89%2B...%2B%EF%BC%881-1%2A55%2F4%EF%BC%89%3D%3F%E6%80%A5.%E6%80%A5.)
165又40/1除以41/1 等以多少,用简便运算,2/1+6/1+12/1+20/1+30/1=?(1+2/1)*(1-2/1)*(1+3/1)*...*(1+9/1)*(1-9/1)=?2001/1+2001/2+2001/3+02001/4+...+2001/2001=?(10-10*55/40+(9-9*55/4)+...+(1-1*55/4)=?急.急.
165又40/1除以41/1 等以多少,用简便运算,
2/1+6/1+12/1+20/1+30/1=?
(1+2/1)*(1-2/1)*(1+3/1)*...*(1+9/1)*(1-9/1)=?
2001/1+2001/2+2001/3+02001/4+...+2001/2001=?
(10-10*55/40+(9-9*55/4)+...+(1-1*55/4)=?
急.急.
165又40/1除以41/1 等以多少,用简便运算,2/1+6/1+12/1+20/1+30/1=?(1+2/1)*(1-2/1)*(1+3/1)*...*(1+9/1)*(1-9/1)=?2001/1+2001/2+2001/3+02001/4+...+2001/2001=?(10-10*55/40+(9-9*55/4)+...+(1-1*55/4)=?急.急.
2、平方差公式
(1+2/1)*(1-2/1)*(1+3/1)*...*(1+9/1)*(1-9/1)=(1-1/4)(1-1/9)(1-1/16).(1-1/81)
=5/9
因为1+2001=2+2000=3+1999=4+1998=.=2*1001
3、(1+2+3+.+2001)/2001=(1000*2002+1001)/2001=1001
4、10(1-55/4)+9(1-55/4)+...+(1-55/4)=(10+9+8+.+1)(1-55/4)
=55*(1-55/4)=51
165又40/1除以41/1那题
165又40/1直接乘41就好了啊 等于8/1353
不知道满意不?
第一题
1/1*2+1/2*3+1/3*4+1/4*5+1/5*6
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=1-1/6
=5/6
1.2/1+6/1+12/1+20/1+30/1=1-(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)=1-1/6=5/6