{(2+3+4)/1 -(3+4+5)/2+(4+5+6)/3-(5+6+7)/4+...+(10+11+12)/9-(11+12+13)/10}/{1-1/2+1/3-1/4+...+1/9-1/10
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/04 05:38:27
![{(2+3+4)/1 -(3+4+5)/2+(4+5+6)/3-(5+6+7)/4+...+(10+11+12)/9-(11+12+13)/10}/{1-1/2+1/3-1/4+...+1/9-1/10](/uploads/image/z/8588366-62-6.jpg?t=%EF%BD%9B%282%2B3%2B4%29%2F1+-%283%2B4%2B5%29%2F2%2B%284%2B5%2B6%29%2F3-%285%2B6%2B7%29%2F4%2B...%2B%2810%2B11%2B12%29%2F9-%2811%2B12%2B13%29%2F10%7D%2F%7B1-1%2F2%2B1%2F3-1%2F4%2B...%2B1%2F9-1%2F10)
{(2+3+4)/1 -(3+4+5)/2+(4+5+6)/3-(5+6+7)/4+...+(10+11+12)/9-(11+12+13)/10}/{1-1/2+1/3-1/4+...+1/9-1/10
{(2+3+4)/1 -(3+4+5)/2+(4+5+6)/3-(5+6+7)/4+...+(10+11+12)/9-(11+12+13)/10}/{1-1/2+1/3-1/4+...+1/9-1/10
{(2+3+4)/1 -(3+4+5)/2+(4+5+6)/3-(5+6+7)/4+...+(10+11+12)/9-(11+12+13)/10}/{1-1/2+1/3-1/4+...+1/9-1/10
=6.
原式={(3+1+2+3)/1-(6+1+2+3)/2+(9+1+2+3)/3-(12+1+2+3)/4+...+(27+1+2+3)/9-(30+1+2+3)/10}/(1-1/2+1/3-1/4+...+1/9-1/10) (将分子里面的每个数提一个分母的值出来)
={[3+(1+2+3)/1]-[3+(1+2+3)/2]+[3+(1+2+3)/3]-[3+(1+2+3)/4]+...+[3+(1+2+3)/9]-[3+ (1+2+3)/10]}/(1-1/2+1/3-1/4+...+1/9-1/10)
={3-3+3-3+...+3-3+(1+2+3)(1-1/2+1/3-1/4+...+1/9-1/10)}/(1-1/2+1/3-1/4+...+1/9-1/10)
={6(1-1/2+1/3-1/4+...+1/9-1/10)}/(1-1/2+1/3-1/4+...+1/9-1/10)
=6
够详细的把.