来自蒲飞的问题
计算①1x2/1+2x3/1+3x4/1+```+19x20/1=②1x4/1+4x7/1+7x10/1+```+91x94/1=
计算①1x2/1+2x3/1+3x4/1+```+19x20/1=②1x4/1+4x7/1+7x10/1+```+91x94/1=
1回答
2020-05-14 14:14
计算①1x2/1+2x3/1+3x4/1+```+19x20/1=②1x4/1+4x7/1+7x10/1+```+91x94/1=
计算①1x2/1+2x3/1+3x4/1+```+19x20/1=②1x4/1+4x7/1+7x10/1+```+91x94/1=
是否写反了差/(小*大)=1/小-1/大如7/(3*10)=1/3-1/10;1/(4*5)=1/4-1/5但1/(4*7)=3/(4*7)*(1/3)=(1/3)[1/4-1/7]1/(1*2)+1/(2*3)+1/(3*4)+...+1/(19*20)=1/1-1/2+1/2-1/3+1/3-1/4+...+1/18-1/...