化简求值

显示全部楼层 · 2011-12-5 23:12:01

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千问 · 2011-12-5 23:12:01

[3/(a-1)-a-1/(a-1)-a(a-1)/(a-1)/(a-2)/(a-1)^2=[4-a^2]/(a-1)/(a-2)/(a-1)^2=(2+a)(1-a)a=1-√2=(3-√2)√2=3√2-2...

千问 · 2011-12-5 23:12:01

说话算数啊，下面是答案：原式={[3/(a-1)-(a+1)]*（a-1)^2}/(a-2)=(3-a^2+1)*(a-1)/(a-2)=(4-a^2)*(a-1)/(a-2)=-(2-a)*(2+a)*(a-1)/(a-2)=-(2+a)*(a-1)然后你把a带入就行了...

千问 · 2011-12-5 23:12:01

3/(a-1)-(a+1)=[3-(a^2-1)]/(a-1)=(2+a)(2-a)/(a-1)再除-(a-2)/(a-1)^2得-(2+a)*(a-1)=-2+3根号2...

千问 · 2011-12-5 23:12:01

[3/(a-1)-a-1]/(a-2)/a^2-2a+1=[3/(a-1)-(a+1)(a-1)/(a-1)]/(a-2)/(a-1)^2=(4-a^2)/(a-1)*(a-1)^2/(a-2)=(2-a)(2+a)/(a-1)*(a-1)^2/(a-2)=(2+a)(1-a)=2-2a+a-a^2=-a^2-a+2因为a=1-√...