比较(a+3)(a-2)与(a+1/2)的大小
题目
比较(a+3)(a-2)与(a+1/2)的大小
答案
(a+3)(a-2)-(a+1/2)
=a^2+a-6-a-1/2
=a^2-13/2
当a=±√26/2时,
a^2-13/2=0
即(a+3)(a-2)-(a+1/2)=0
所以(a+3)(a-2)=(a+1/2)
当a>√26/2 或x0
即(a+3)(a-2)-(a+1/2)>0
所以(a+3)(a-2)>(a+1/2)
当-√26/2
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