[(1/31+1/37+1/41+1/47+1/53+1/69)*(1/29+1/31+1/37+1/41+1/47+1/53

分类: 作业答案 • 2022-03-22 19:56:01

问题描述：

[(1/31+1/37+1/41+1/47+1/53+1/69)*(1/29+1/31+1/37+1/41+1/47+1/53
)]-[(1/29+1/31+1/37+1/41+1/47+1/53+1/69)*(1/31+1/37+1/41+1/47+1/53)]

答

设 a=1/31+1/37+1/41+1/47+1/53,b=1/29+1/31+1/37+1/41+1/47+1/53
原式=(a+1/69)b-(b+1/69)a=ab-ba+1/69 * (b-a)=1/(69*29)=1/(69*29)