计算5/4×9+5/9×14+5/14×19+.+5/34×39+5/39×44+5/44×49

来源:学生作业帮助网 编辑:作业帮 时间:2024/04/29 08:48:05
计算5/4×9+5/9×14+5/14×19+.+5/34×39+5/39×44+5/44×49

计算5/4×9+5/9×14+5/14×19+.+5/34×39+5/39×44+5/44×49
计算5/4×9+5/9×14+5/14×19+.+5/34×39+5/39×44+5/44×49

计算5/4×9+5/9×14+5/14×19+.+5/34×39+5/39×44+5/44×49
5/4×9+5/9×14+5/14×19+.+5/34×39+5/39×44+5/44×49
=1/4-1/9+1/9-1/14+1/14-1/19+.1/34-1/39+1/39-1/44+1/11-1/49
=1/4-1/49
=49/196-4/196
=45/196

真不知道。。。

5/4×9+5/9×14+5/14×19+.........+5/34×39+5/39×44+5/44×49
=(1/4-1/9)+(1/9-1/14)+(1/14-1/19)+.........+(1/34-1/39)+(1/39-1/44)+(1/44-1/49)
=1/4-1/9+1/9-1/14+1/14-1/19+.........+1/34-1/39+1/39-1/44+1/44-1/49
=1/4-1/49
=45/196