1234567890/(1234567891)2−1234567890×1234567892.
问题描述:
. 1234567890 (1234567891)2−1234567890×1234567892
答
设1234567891=A,则1234567890=A-1,1234567892=A+1,
原式=
A−1
A2−(A−1)(A+1)
=
,A−1
A2−(A2−1)
=A-1,
=1234567891-1,
=1234567890.